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Solutions - Class 12 Engineering Chemistry - Extra Questions

The mass percentage of nitrogen in histamine is _______.



An ideal aqueous solution containing liquid A(M.Wt=128) 64% by weight has a vapour pressure of 145mm Hg. If the vapour pressure of A is x mm of Hg and that of water is 155mm Hg at the same temperature. Then find x5. The solutions is ideal.



Does a new substance form when a solute dissolves in a solvent?



Calculate the percentage of magnesium in magnesium carbonate.



Mention names of four methods of expressing concentration of a solution.



Calculate percentage of oxygen present in CO2. [Atomic mass of O=16u. C=12u]



At constant temperature and pressure, one mole of a pure substance free energy is identical with:



Van't Hoff factor for an electrolyte is greater than _____.



For strong electrolytes, van't Hoff factor 'i' equals to total number of _____ (ions/atoms) in the formula unit.



Van't Hoff factor for TH(NO3)4 in an aqueous solution is  :



At 25oC benzene and toluene have densities 0.879 and 0.867 g/mL respectively. Assuming that benzene, toluene solutions are ideal, then the equation for the density (e) of solution as: e=1100[0.879V+0.867(100V)] where V is the volume of benzene.

If true enter 1 else enter 0.



Match column I with column II



Match column I with column II



For weak electrolytes, van't Hoff factor 'i' is a measure of the degree of dissociation of weak electrolyte.
If true enter 1, if false enter 0.



Van't Hoff factor of a mixture of two moles of KI with 1 mole HgI2 in a solution of water is :



What is the difference between lyophobic sol and lyophilic sol ?



How is the vapour pressure of a solvent affected when a non-volatile solute is dissolved in it ?



For an ideal solution, ΔmixH is _______  .



For an ideal solution, ΔmixV is



The vapour pressure of water is 12.3 kPa at 300 K. Calculate the vapour pressure of 1 molal solution of a non-volatile solute in it.



Vapour pressure of water at 293 K is 17.535 mm Hg. Calculate the vapour pressure of water at 293 K when 25 g of glucose is dissolved in 450 g of water.



Based on solute-solvent interactions, arrange the following in order of increasing solubility in n-octane and explain. 
Cyclohexane, KCl, CH3OH, CH3CN



Define the term solution. How many types of solutions are formed? Write briefly about each type with an example.



Define an ideal solution and write one of its characteristics.



Arrange the following compounds in increasing order of solubility in water:
         C6H5NH2,(C2H5)2NH,C2H5NH2



A 1.00 molal aqueous solution of trichloroacetic acid (CCl3COOH) is heated to its boiling point. The solution has the boiling point of 100.8oC. Determine the van 't Hoff factor for trichloroacetic acid. (Kb for water 0.512 K kg Mol1)

                                                                 OR

Define the following terms:

(i) Mole fraction

(ii) Isotonic solutions

(iii) Van 't Hoff factor

(iv) Ideal solution

 



Vapour pressure of three liquids A, B, C are in their ascending order. Identify the liquid that has least critical temperature in its gaseous state.



A mixture containing four miscible liquids P, Q, R, and S are subjected to fractional distillation. Liquid P is distilled off first, into the receiver flask. Then S, followed by R and Q is left behind in the distillation flask. Based on the above observations, arrange the liquids in ascending order of their vapour pressures.



Why is be solubility of NaCl in water 311gl1 N but is zero in benzene?



What is the value of ΔHmix for an ideal solution ?



a. Which gas is dissolved in soft drinks?
b. What will you do to increase the solubility of this gas ?



What happens to vapour pressure of water if a tablespoon of sugar is added to it?



What will be the value of van't Hoff factor (i) of benzoic acid if it demerises in aqueous solution? How will the experimental molecular weight vary as compared to the normal molecular weight?



What will be the value of Van't Hoff factor for ethanoic acid in benzene?



Derive van't Hoff general solution equation.



What is relative lowering of vapour pressure? How is it useful to determine the molar-mass of a solute?



The vapour pressure of pure benzene at a certain temperature is 0.850 bar. A non-volatile, non-electrolyte solid weighing 0.5 g when added to 39 g of benzene (molar mass 78 g mol1), vapour pressure becomes 0.845 bar. What is the molar mass of the solid substance?



'The extent to which a solute is dissociated or associated can be expressed by Van 't Hoff factor'. Substantiate the statement.



Derive the relationship between relative lowering of vapour pressure and molar mass of solute.



Alkaline solution of HgCl2 and KI is called _________.



Mention the enthalpy of mixing (mixH) value to form an ideal solution.



Heptane and octane form ideal solution. At 373 K, the vapour pressures of the two liquids are 105.2 kPa and 46.8 kPa respectively. What will be the vapour pressure, in bar, of a mixture of 25 g heptane and 35 g of octane?



An aqueous solution containing 28% by mass of a liquid A (mol. mass = 140) has a vapour pressure of 160 mm of 37oC. Find the vapour pressure of the pure liquid A (The vapour pressure of water at 37oCis 150 mm).



Potassium ferrocyanide is 50% ionised in aqueous solution. Its van't Hoff factor will be:



A solution containing 8.44g of sucrose in 100g of water has a vapour pressure 4.56mm of Hg at 273K. If the vapour pressure of pure water is 4.58mm of Hg at the same temperature, calculate the molecular weight of sucrose.



Calculate the vapour pressure of an aqueous solution of 1.0 molal glucose solution at 100oC.



The vapour pressure of two pure liquids A and B forming an ideal solution are 400 mm Hg and 800 mm Hg respectively at temperature I. A liquid mixture containing 3:1 molar composition of A and B is present in a cylinder closed by a piston so that the pressure can be varied. The solution is slowly vaporised at temperature I by decreasing the applied pressure from a starting of 760 mm Hg. A pressure gauge (in mm Hg) is connected



A cylinder fitted with an air tight piston contains a small amount of a liquid at a fixed temperature. The piston is moved out so that the volume increases
(a) What will be the effect on the change of vapour pressure initially?
(b) How will the rates of evaporation and condensation change initially?
(c) What will happen when equilibrium is restored finally and what will be the final vapour pressure? 



The freezing point of a solution containing 5.85 g of NaCl in 100g of water is 3.348oC. Calculate van't Hoff factor 'i' for this solution. What will be the experimental molecular weight of NaCI?
(Kf for water = 1.86Kkgmol1, at. wt. Na = 23, Cl = 35.5)



Two moles of O_2 gas is collected over water at 400 K temperature in 2 litre vessel. If the pressure of dry O_2 gas is 32.20 bar then find the vapour pressure of water under the same conditions.



The vapour pressure of a pure liquid at 25 is 100 mm Hg. Calculate the relative lowering of vapour pressure if the mole fraction of solvent in solution is 0.8.



Identify the solute & the solvent in the following solution:
a) sugar solution
b) Air
c) Rain water
d) Aerated drinks



A mixture of two miscible liquids A and B is distilled under equilibrium conditions at 1 atm pressure. The mole fraction of A in solution and vapour phase are 0.30 and 0.60 respectively. Assuming ideal behaviour of the solution and the vapour. Calculate the ratio of the vapour pressure of pure A to that of pure B.



Define an ideal solution.



At 90^oC, the vapour pressure of toluene is 400 Torr and that of o-xylene is 150 Torr. What is the composition of the liquid mixture that boils at 90^oC when the pressure is 0.50 atm? What is the composition of the vapour produced?



Calculate the following.
The vapour pressure of the solution at 298 K.



At 25^oC the saturated vapour pressure of water is 3.165 kPa (23.75 mm Hg). Find the saturated vapour pressure of a 5\% aqueous solution of urea (carbamide) at the same temperature. (Molar mass of urea =60.05 g mol^{-1})



The vapour pressure of an aqueous solution of glucose is 750mm at 373K. find molality and mole fraction



Identify the solute & the solvent in the following solutions:
(a) Sugar solution (b) Air (c) Grains (d) Aerated drinks.



Derive the relationship between relative lowering of vapour pressure and mole fraction of the volatile liquid.



Out of two 0.1 molal solutions of glucose and of potassium chloride, which one will have a higher boiling point and why?



400\ g of 20\%\ (w/w) solution is cooled. 50\ g of solute is precipitated. What is the %(w/w) of solute in the remaining solution?



Vapour pressure of liquids A and B at 298\ K is 300\ mm\ Hg  and 450\ mm\ Hg. Calculate the mole fraction of A in the mixture. 

[Given total vapour pressure of solution=405\ mm\ Hg.]



The vapor pressure of water is 12.3 \text { }KPa at 300K. Calculate the vapor pressure of 1 molal solution of a non-volatile solute in it. 



What is vapour pressure?



The vapour pressure of water is 92mm at 323K. 18.1g of urea are dissolved in 100g of water. The vapour pressure is reduced by 5mm. Calculate the molar mass of urea.



If equal volume of { BaCl }_{ 2 } and NaF solutions are mixed , which of these combination will  give a precipitate? 
{ K }_{ sp } of { BaF}_{ 2}  ={ 1.7\times 10 }^{ -7 }.



The vapour pressure of a pure liquid A is 80 mmHg at 300K. It forms an ideal solution with liquid B. When the mole fraction of B is 0.4, the total pressure was to be 88mmHg. The vapour pressure of liquid B would be?



The vapour pressure of solution of 5g of non electrolyte in 100 g of a water at a particular temperature is 2985 N{ m }^{ -2 }. The vapour pressure of pure water at that temperature is 3000 N{ m }^{ -2 }



What is the mass of a non volatile solute (molecular mass 60) that needs tobe dissolved in 100 g of water In order to decrease the vapour pressure of water by 25% .What will be the velocity of solution?



If p° and p are the vapour pressure of a solvent and it's solution repetitively and N1 and N2 are the mole fractions of the solvent and solute respectively, then the relation between them is?



The vapour pressure of pure water is 23.8 mm Hg at 25^0C What is the vapour pressure of 2.50 molal C_6H_{12}O_6.



2 g benzoic acid (C_{6}H_{5}COOH) dissolved in 25 g of benzene shoes a depression in freezing point equal to 1.62 K. Molal depression constant for benzene is 4.9 K kg mol^{-1}. What is the percentage association of acid if it forms dimer in solution?



Explain homogenous and heterogenous conditions with an example.



Derive van"t Hoff equation for osmotic pressure of a solution.



A sample of O_{2} gas is collected over at 23^{o}\ C at a barometric pressure of 751\ mm\ Hg (vapour pressure of water at 23^{o}\ C is 21\ mmHg). The partial pressure of O_{2} gas in the sample collected is



A 0.2\%   aq. sol. of a non-volatile solution exerted a VP of 1.004 bar at 100^\circ C. What is the molar mass of the solute ? 
(Given V.P of mass water at 100^\circ C is 1.013 bar and molar mass of water is 18\,g/mol).



A 821 mL N_2(g) was collected over liquid water at 300 K and 1 atm. If vapour pressure of H_2O is 30 torr then moles of N_2(g) in moist gas mixture is :



Define Van't Hoff's factor.



The vapour of a sodium containing 13\times 10^{-3}\ kg of solute in 0.1\ kg of water at 298\ K is 27.371\ mm\ Hg. Calculate the molar mass of the solute. Given that the vapour pressure of water at 298\ K is 28.065\ mm\ Hg .



Find its mass of urea dissolved in 100g H_2O which decreese the vapour presure of solvent by 20\%



110g of salt is present in 550g of solution. Calculate the mass percentage of the solution.



The vapour pressure of pure water at is 25.21 torr. What is the vapour pressure of a solution which contain 20.0 glucose, {C_6}{H_{{\text{12}}}}{{\text{O}}_6} in 70 g water ?



Two A and B in a mixture produced 550 mm of Hg vapour pressure. If their vapour pressure in the pure states are 400 mm of Hg and 600 mm of Hg respectively. What is the vapour pressure of 'A' in the mixture?



Calculate the percentage by mass to volume for 0.2 M NaOH solution. 



What is the number of molecules in 1.5 moles of ammonia ?



When HgI_2 is added to aqueous solution of KI, why there is an increase in vapour pressure of solution ?



Under what condition the van't Hoff factor is greater than one?



100 g of liquid A (mol. mass of = 140 g/mol) was dissolved in 1000 g of liquid B (molar mass of  = 180 g/mol). The vapour pressure of pure liquid B was found to be 500 atmosphere. Calculate the vapour pressure of liquid A and its vapour pressure in the solution, if the total vapour pressure of the solution is 475 atmosphere. 



Predict whether van't HOff factor (i) is less than one or greater than one in the following:
(i) CH_3COOH dissolved in water
(ii) CH_3COOH dissolved in benzene



The vapour pressure of water at 20^oC is 17mm Hg.Calculate the vapour pressure of a solution containing 2.8 g of urea (NH_2CONH_2) in 50g of water (16.71mm Hg).



Octane is a component of gasoline. Complete combustion of octane leads to CO_2 and H_2O while incomplete combustion produces CO and H_2O, which not only reduced the efficiency of the engine using the fuel but is also toxic.In a certain test run, gallon of octane is burned in an engine, The total mass of CO, CO_2 and H_2O produced is 9.768\ kg. Calculate the efficiency of the process, i.e, calculate the percentage of octane converted to CO_2. The density of octane is 2.28\ kg/gallon



In 1.684\ g sample of a mixture of MgSO_{4}.7H_{2}O and MgCl_{2}.6H_{2}O containg some inert impurity was subjected to suitable treatment, as a result of which there were obtained 0.699\ g of BaSO_{4} adn 0.888\ g of Mg_{2}P_{2}O_{7}. The mass percentage of impurity is (Ba=137, Mg=24, P=31)



A 1.174\ g sample of special grade steel was treated approximately with Chugaev's reagent by which nickel was precipitated as nickel dimethylglyoxime NiC_{8}H_{14}O_{4}N_{4}. The dried precipitate weighed 0.2136\ g
The percentage of nickel in the steel being analysed is (Ni=58.7)



A blackened silver coin weighing 15\ g on treatment with HCl yielded 25\ mL of H_{2}S at 12^{o}C and 775\ mm pressure. What percentage of original silver tarnished?



3\ g sample of blue vitrol (CuSO_{4}.5H_{2}O) were dissolved in water. BaCl_{2} solution was mixed in excess to this solution. The precipitate obtained was washed and dried. It weighed 2.82\ g. Determine \% of SO_{4}^{2-} by weight in sample.



What is the percentage by volume of gases in the atmosphere?



An aqueous solution containing 20\% by weight of liquid X(mol. wt. =140) has a vapour pressure 160\ mm at 60^{o}C. Calculate the vapour pressure of pure liquid X if the vapour pressure of water is 150\ mm at 60^{o}C



Which of the following aqueous solutions has a higher vapour pressure if the density of water is 1\ g/cc?
(1) Solution having mole fraction of cane sugar =0.1
(2) Solution having molal concentration = 1 m
[Give your answer in terms of 1 or 2, e.g. enter 1 if (1) is true.]



Which of the following aqueous solutions has a higher vapour pressure if the density of water is 1\ g/cc?
Solution having molal concentration =1\ m



What is the vapour pressure at 100^{o}C of a solution containing 15.6\ g of water and 1.68\ g of sucrose (C_{12}H_{22}O_{11})?



Find the percentage of nitrogen in an organic compound analysed by Kjeldahl method. 1.61 \,g of the compound produced NH_3 which was absorbed in 250 \,mL of \dfrac{N}{2}H_2SO_4 solution.The remaining acid was then diluted to one litre,25 \,mL of which required 25.5 \,mL of \dfrac{N}{10} NaOH for exact neutralization.



One litre of water was added to 500\ mL of 32\%\ HNO_{3} of density 1.20\ g/mL. What is the per cent concentration of HNO_{3} in the solution obtained?



At 25^{o}C benzene and toluene have densities 0.879 and 0.867\ g/cc respectively.
Assuming that benzene-toluene solutions are ideal. establish the equation for the density of the solution.
d=\dfrac{1}{100}\left\{0.879\ V+0.867 (100-V)\right\}where V is the volume per cent of benzene.



0.5\ g of a nonvolatile organic compound (mol.wt. 65) is dissolved in 100\ mL of CCl_{4}. If the vapour pressure pure CCl_{4} is 143\ mm, what would be the vapour pressure of the solution? (Density of CCl_{4} solution is 1.58\ g/cc)



Determine the per cent concentration of a solution obtained by mixing 300\ g of a 25\% and 400\ g of a 40\% solution.



When 10mL of ethanol of density 0.7893 g/L is mixed with 20 mL of water of density 0.9971 g/L at 25^oC, the final solution has a density of 0.9571 g/L. Calculate the percentage change in total volume on mixing.



A solution contains 1 milli-curie of L-phenyl alanine C^{14} (uniformly labelled) in 2.0\ mL solution. The activity of the labelled sample is given as 150 milli-curie/milli-mole. Calculate:
(a) The concentration of the sample in the solution in mole/litre.
(b) The activity of the solution in terms of counting per minute/mL at a counting efficiency of 80\%.



Calculate the concentration of a solution obtained by mixing 300\,g \,25% by weight solution of NH_4Cl and 150\,g of 40% by weight solution of NH_4Cl.



If the vapour pressure of pure liquids A and B are 300 mm and 800 mm Hg at 75^oC, calculate the composition of the mixture such that it boils at 75^oC. Find the composition of the vapour phase.



Calculate the % of free SO_3 in oleum (a solution of SO_3 in H_2SO_4) that is labelled 109% H_2SO_4 by weight.



A 0.5 g sample containing MnO_2 is treated with HCl, liberating Cl_2. The Cl_2 is passed into a solution of KI and 30.0 cm^3 of 0.1M Na_2S_2O_3 are required to titrate the liberated iodine. Calculate the percentage of MnO_2 in the sample.



What type of liquids form ideal solutions? 



Explain the solubility rule "like dissolve like" in terms of intermolecular forces that exist in solutions. 



State any two characteristics of ideal solutions. 



Neutralisation of 30 \,gm of a mixture of acetic acid and phenol solutions required 100 \,ml of 2M sodium hydroxide solution. When the same mixture was treated with bromine water, 33.1 \,gm of precipitate was formed. Determine the mass percentage of acetic acid and phenol in the given solution.



Define w/w (percentage mass by mass) way of expressing concentrations.



Both Sarika and Mohan were asked to make a salt solution. Sarika was given a teaspoonful of salt and half a glass of water, whereas Mohan was given twenty teaspoons full of salt and half a glass of water.
(a) How would they make salt solutions?
(b) Who would be able to prepare a saturated solution?



Match the terms given in Column I with expressions given in Column II.



Match the items given in Column I with Column II.



Why is the vapour pressure of an aqueous solution of glucose lower than that of water?



Define the v/v (volume by volume percentage) mode of expressing the concentration of a solution.



Concentration terms such as mass percentage, ppm, mole fraction and molality are independent of temperature, however molarity is a function of temperature. Explain.



Will honey form a solution in water? (Yes/No)



Define saturated solution



Differentiate between the following. 
Solution and Suspension



Give an example of a reaction where the following are involved in a Solution



Define Seeding.



Explain why a solution is always clear and transparent.



Suggest a suitable technique to separate the constituents of the following mixtures. Also give the reason for selecting the particular method.
(a) Salt from sea water
(b) Ammonium chloride from sand
(c) Chalk powder from water
(d) Iron from sulphur
(e) Water and alcohol 
(f) Sodium chloride and potassium nitrate
(g) Calcium carbonate and sodium chloride



Will sodium carbonate form a solution in water? (Yes/No)



What type of solutions are formed on dissolving different concentrations of soap in the water?



Calculate the mass of 95\% pure MnO_2 to produce 35.5 \,g of Cl_2 as per the following reaction:
MnO_2 + 4HCl \rightarrow {}MnCl_2 + Cl_2 + H_2O. (At. mass of Mn = 55)



A solution of sodium hydroxide contains 4.8 \,g of the substance per dm^3, 
What volume of water has to be added to one dm^3 of the solution in order to make it exactly decinormal ?



Define: Mass percentage.



Which one in each of the following pairs of liquids is more viscous: coconut oil, castor oil



What do you mean by decinormal solution ?



Calculate the volume of concentrated nitric acid of normality 14 required to prepared 1 \,dm^3 of \dfrac{N}{10} nitric acid.



Calculate the percentage of nitrogen in NH_4. (Atomic mass of N = 14, H = 1 amu)



1 \cdot 5 \mathrm{g} of pyrolusite ore were treated with 10 g of Mohr's salt and dilute \mathrm{H}_{2} \mathrm{SO}_{4} . Atter the reaction, the solution was diluted to 250 \mathrm{cm}^{3} .   50 cm ^{3} of diluted solution required 10 \mathrm{cm}^{3} of 0 \cdot 1 \mathrm{N} \mathrm{K}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7} solution.
Find out percentage of pure \mathrm{Mn} \mathrm{O}_{2} in pyrolusite.



1 \cdot 1 g of a sample of copper ore is dissolved and \mathrm{Cu}^{2+}(a q) is treated with KI. The iodinethus liberated required 12 \cdot 12 \mathrm{cm}^{3} of 0.1 \mathrm{M} \mathrm{Na}_{2} \mathrm{S}_{2} \mathrm{O}_{3} solution for titration. What is the percentage of copper in the ore?



What are the factors affecting the solubility?



5 \cdot 0 g of a sample of brass were dissolved in 1 litre dil. \mathbf{H}_{2} \mathbf{S O}_{4} \cdot \mathbf{2 0} \operatorname{cm}^{3} of this solution weremixed with KI and liberated lodine required 20 \mathrm{cm}^{3} of 0 \cdot 0327 \mathrm{M} hypo solution for titration. Calculate the percentage of copper in the alloy. 



1 \cdot 5 \mathrm{g} of pyrolusite ore were treated with 10 g of Mohr's salt and dilute \mathrm{H}_{2} \mathrm{SO}_{4} . Atter the reaction, the solution was diluted to 250 \mathrm{cm}^{3} .   50 cm ^{3} of diluted solution required 10 \mathrm{cm}^{3} of 0 \cdot 1 \mathrm{N} \mathrm{K}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7} solution.
Find out percentage of pure \mathrm{Mn} \mathrm{O}_{2} in pyrolusite.



Calculate the mass percentage of different elements present in sodium sulphate.



In an ore, the only oxidisable material is S n^{2+} . This ore is titrated with a dichromate solution containing 2 \cdot 58 of \mathrm{K}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7} in 0.50 litre. The 0.40 \mathrm{g} sample of the ore required 10.0 \mathrm{cm}^{3} of titrant to reach equivalent point. Calculate the percentage of the in the ore. (K=39 \cdot 1, C r=52, S n=118 \cdot 7)



(i) 200 {cm}^{3} of aqueous solution of a protein contains 1.26 g of protein. The osmotic pressure of solution at 300 K is found to be 8.3 \times {10}^{-2} bar. Calculate the molar mass of protein. \left(R = 0.083 l bar {K}^{-1} {mol}^{-1}\right)
(ii) What is the significance of Van't Hoff factor?



Derive the relationship between relative lowering of vapour pressure and molar mass of non-volatile solute.



Amongst the following compounds, identify which are insoluble, partially soluble and highly soluble in water?
(i) phenol (ii) toluene (iii) formic acid (iv) ethylene glycol (v) chloroform (vi) pentanol



Two liquids A and B form an ideal solution. At 300 K, the vapour pressure of a solution containing 1 mole of A and 3 mole of B is 550 mm of Hg. At the same temperature, if one more mole of B is added to this solution, the vapour pressure of the solution increases by 10 mm of Hg. Determine the vapour pressure of A and B in their pure states.



Match the items of Column-I with its proportional term in the items of Column-II:
Column-I  Column-II
(a) Kinetic energy  (p) Mole fraction
(b) Partial pressure of a gas (q) Density 
(c) Rate of diffusion  (r) Molar mass
(d) Vapour pressure of a liquid(s) Absolute temperature 



The answer to this question is a single digit integer, ranging from 0 to 9.

The van't Hoff factor for aqueous solution of CuSO_4 \cdot 5H_2O will be ...



A solution of a non-volatile solute in water freezes at -0.3^0 C .If vapour pressure of pure water at 298 K is 23.51 mm of Hg and K_f for water in 1.86 degree/molal .Calculate the vapour pressure of this solution at 298 k.



At 80C, the vapour pressure of pure benzene is 753 mm Hg and of pure toluene 290 mm Hg. Calculate the composition of a liquid in mole per cent which at 80C is in equilibrium with the vapour containing 30 mole per cent of benzene.



Two solids X and Y dissociate into gaseous products at a certain temperature as follows:
X(s) \rightleftharpoons A(g) + C(g), and Y(s) \rightleftharpoons B(g) + C(g). At a given temperature, pressure over excess solid X is 40\ mm and total pressure over solid Y is 60\ mm. When they are preset in separate containers. Calculate
(a) the values of K_{p} for two reactions (in mm)
(b) the ratio of moles of A and B in the vapour state over a mixture of X and Y.
(c)The total pressure of gases over a mixture of X and Y.



Two solutions of A and B are available. The first is known to contain 1 mole of A and 3 moles of B and its total vapour pressure isAtm. The second is known to contain 2 moles of A and 2 moles of B; its vapour pressure is greater than 1 atm, but it is found that this total vapour pressure may be reduced to 1 atm by the addition of 6 moles of C. the vapour pressure of pure C is 0.80 atm. Assuming ideal solutions and that all these data refer to 25C, calculate the vapour pressureof pure A and of pure B.



Vapour pressure of water at certain temperature is 155mm Hg and that of the another solvent 'X' is 'p' mm Hg. Molecular weight of 'X' is 128. An aqueous solution of 'X'(64\% by wt) has a vapour pressure of 145mm Hg. What is 'p'?



Vapour pressure of chloroform (CHCl_{3}) and dichloromethane (CH_{2}Cl_{2}) at 298\ K are 200\ mm\ Hg and 415\ mm\ Hg respectively.
(i) Calculate the vapour pressure of the solution prepared by mixing 25.5\ g of CHCl_{3} and 40\ g of CH_{2}Cl_{2} at 290\ K and
(ii) Mole fraction of each component in solution.



Calculate the weight of a non-volatile solute (mol./wt. 40) which should be dissolved in 114\ g octane to reduce its vapour pressure to 80%.



Vapour pressure of pure benzene is 640\ mm and its mol. wt. is 78. When 2.175\ g of a non-volatile substance is dissolved in 39g benzene the vapour pressure of the solution becomes 600\ mm. Calculate mol. wt. of solute.



Two gases in adjoining vessels are brought into contact by opening a stop cock between them. The one vessel measured 0.25 lit and contained NO at 800 torr and 220 K, the other measured 0.1 lit and contained O_2 at 600 torr. The reaction to form N_2O_4 (solid) exhausts the limiting reactant completely.
a) Neglecting the vapour pressure of N_2O_4 what is the pressure of the gas remaining at 220 K after completion of the reaction?
b) What weight of N_2O_4 is formed?
[Given that : \displaystyle \frac {342.8}{760}\,\times\, \frac {0.35}{0.082}\,\times\, \frac{1}{22}\,=\,8.75\,\times\,10]



The vapour pressure of chloroforms and de-chloroforms at 298 k are 200 mm Hg and 415 mm Hg? calculate the vapour pressure of solution by mixing 25.5 gram of CHCl_3 40 gram of CH_2Cl_2. calculate the mole fraction of each component on vapour phase.   



Van't Hoffs factor for a solution is less than one, what is the conclusion drawn from it.



At 400^oC, the vapour pressure of water is 55.3mm\ Hg. Calculate the vapour pressure at the same temperature over 10\% aqueous solution of urea [CO(NH_2)_2]?



The vapor pressure of water at 80^ {\circ}C is 355 torr. A 100\, ml vessel contained water-saturated oxygen at 80^ {\circ}C the total gas pressure being 760 torr. The contents of the vessel were pumped into a 50.0 ml, vessel at the same temperature, What were the partial pressure of oxygen and of water vapor, what was the total pressure in the final equilibrated state? Neglect the volume of any water which might condense.



Three grams of activated charcoal was added to 50ml of acetic acid solution (0.06 N) in a flask. After an hour it was filtered and the strength of the filtrate was found to be 0.042 N. Amount of acetic acid adsorbed (per gram of charcoal) is:



Vapour pressure of pure water at 298\ K is 23.8\ mm\ Hg. 50\ g of urea (NH_2CONH_2) is dissolved in 850\ g of water. Calculate the vapour pressure of water for this solution and its relative lowering.



Two liquids A and B form an ideal solution at temperature T. When the total vapour pressure above the solution if 600\ torr, the amount fraction of A in the vapour phase is 0.40 and in the liquid phase is 0.6. What are the vapour pressure of pure A and B at temperature T?



Solution of two volatile liquid x and y obey Raoult's law. At a certain temperature it is found that when the total pressure above a given solution is 400\ mm of Hg, the mole fraction of x in the vapour is 0.45 and in the liquid is 0.65. what are the vapour pressure of two pure liquids at the given temperature?



The vapour pressure of two pure liquids A and B which from an ideal solution are 500 and 800 torr respectively at 300\ K. A liquid solution A and B for which the mole fraction of A is 0.60 is contained in a cylinder closed by a piston on which the pressure can be varied. What will be the pressure when 1 mol of the mixture has been vaporized?



Vapor pressure of pure water at 298 \ K is 23.8 \ mmHg. 50 \ g of urea is dissolved in 850 \ g of water. Calculate the vapor pressure of water for this solution and it's relative lowering.



Two liquids A and B boils at 145^{o}C and 190^{o}C. Which of them has higher vapour pressure at 80^{o}C?



The vapour pressure of pure water is 23.8\ mmHg at 25^{0}\ C. What is the vapour pressure of 2.50\ molal\ C_{6}H_{12}O_{6}?



The normal boiling of water is 373 K. Vapour pressure of water at temperature T is 19 mm Hg. If enthalpy of evaporation is 40.67 kJ/mol, then temperature T would be: 
(Use log 2 =0.3,R =8.3 { JK }^{ -1 })



For a dilute solution containing 2.5 grams of non volatile non electrolyte solute in hundred grams of water, the elevation in the boiling point at 1 atmosphere pressure is to degree Celsius asuming concentration of solute is much lower than concentration of solvent, the vapour pressure of the solution is?



Quantity of gas occupies 100m,then it is collected on surface of water at 15C and 760mm of Hg. It occupies 91.9ml in dry state at STP conditions. Calculate vapour pressure of {H}_{2}O at 15C.



By adding a non-volatile salute into a solution vapour pressure is reduces.



Give the differences between colloidal solution, true solution and suspension? (at least 2 differences)



Liquids 'A' and 'B' form an ideal solution. Calculate the vapour pressure of solution having 40 mole-percent of 'A' in the vapour at equilibrium. 
(P^0_A = 80cm Hg, P^0_B = 30cm Hg)



Solve it 
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Urea forms an ideal solution in water. Determine the V.P of an aqueous solution containing 10\% by mass of urea at 40^\circ C. (Vapour pressure of water at 40^oC=55.3 mm Hg)



{P_T} = P\mathop A\limits^ \circ  {X_P} - P\mathop B\limits^ \circ  {X_B}
P_T = P \mathring{A} X_P - P \mathring{B} (1 - X_A)
{P_T} = P\mathop A\limits^ \circ  {X_A} + P\mathop B\limits^ \circ   - P\mathop B\limits^ \circ  {X_A}
{P_T} = P\mathop B\limits^ \circ   + \left( {P\mathop {A - P\mathop B\limits^ \circ  }\limits^ \circ  } \right){X_A}



0.6 ml of acetic acid (C{H_3}COOH) having density 1.06 g/ml is dissolved in 1 litre of water. The depression in freezing point observed for this strength of acid was 0.0205\,{\,^0}C. Calculate the Van't Hoff factor and the dissociation constant of acid.



Why is the vapour pressure of a solution of glucose in water lower than that of water?



A quantity of 1.245 g of CuSO_{4}.xH_{2}O was dissolved in water and H_{2}S was passed into it till CuS was completely precipitated. The H_{2}SO_{4} produced in the filtrate required 10 ml of M - NaOH solution. Calculate x.



A sample of chalk contain as impurity a form of clay which losses 14.5\% if its weight as water on along heating. A 5\ g of chalk sample, on heating shows a loss in weight by 1.507\ g. The mass percentage of CaCO_3 in the chalk sample is (Ca=40)



A quantity of 2.7\ g of an alloy of copper and silver was dissolved in moderately concentrated   HNO_{3}, and excess of HCl was added to this solution when 2.87\ g of a dry precipitate is formed. Calculate the percentage of copper in the alloy. 
(Cu=63.5\ ,\ Ag=108)



A gas mixture contains CH_4 and C_3H_6. When this mixture undergo cracking into C(s) and H_ 2(g)m the total number of moles of H_2(g) obtained is 42. If the total volume of the initial gas mixture at 1.5\ atm and 27^oC is 246.3\ L, what is the mole per cent of CH_4 gas in the initial mixture?  



To analyse cast iron for its sulphur content, a 6.4\ g portion of the iron was weighed out for analysis and treated as follows: it was dissolved in hydrochloric acid, the hydrogen sulphide evolved from iron sulphide was distilled off and made to be absorbed by a solution of a cadmium salt, after which CdS was treated with an excess of a solution of CuSO_{4} and the CuS precipitated formed was ignited. As a result 0.795\ g of an ignited CuO precipitate was obtained. Calculate the percentage content of sulphur in the cast iron (Cu=63.5)



A mixture containing As_{2}S_{3}  and As_{2}S_{5} requires 20 ml of 0.05 N iodine for titration. The resulting solution is then acidified and excess of KI was added. The liberated iodine required 1.24g hypo, Na_{2}S_{2}O_{3}.5H_{2}O , for complete reaction.The reactions are :
As_{2}S_{3}+2I_{2}+2H_{2}S \rightarrow As_{2}S_{5}+4H^{+}+4I^{-}
As_{2}S_{5}+4H^{+}+2I^{-}\rightarrow As_{2}S_{3}+2I_{2}+2H_{2}S
The mole percent of As_{2}S_{3} in the original mixture is (As= 75)



A 0.2 g sample of chromite was fused with excess of Na_{2}O_{2} and brought into solution according to reaction:

2Fe\left ( CrO_{2} \right )_{2}+7Na_{2}O_{2} \rightarrow 2NaFeO_{2}+4Na_{2}CrO_{4}+2Na_2O

The solution was acidified with dil. HCl and 1.96 g Mohr's Salt (molar mass = 392 g/mol ) was added. The excess of Fe^{2+} required 40 ml of 0.05N - K_{2}Cr_{2}O_{7} for titration. What is the percent of Cr in sample ? (Cr = 52, Fe = 56) 



A 10g mixture of Cu_{2}S and CuS was treated with 400 ml of 0.4M - MnO_{4}^{-} in acid solution producing SO_{2},Cu^{2+} and Mn ^{2+}. The SO_{2} was boiled off ans the excess of MnO_{4} was titrated with 200ml of 1M-Fe^{2+} solution. The percentage of CuS in original mixture is (Cu=64)



A quantity of 1.6\ g of pyrolusite ore was treated with 50\ ml of 1.0\ N oxalic acid and some sulphuric acid. The oxalic acid left undecomposed was raised to 250\ ml in a flask. A volume of 25\ ml of this solution when titrated with 0.1\ N\ KMnO_4 required 32\ ml of the solution. The percentage of available oxygen in the ore is: 



One gram of commercial AgNO_{3} is dissolved in 50 ml of water. It is treated with 50 ml of a KI solution.The silver iodide thus precipitated is filtered off. Excess of KI is titrated with M/10-KIO_{3} solution in the presence of 6M - HCl till all iodide ions are converted into ICl. It requires 50 ml of M/10-KIO_{3} solution. A 20 ml of the same stock solution of KI requires 30 ml of M/10-KIO_{3} under similar conditions. The percentage of AgNO_{3} in the sample is (Ag=108)
Reaction:
KIO_{3}+2KI+6HCl
\rightarrow 3ICI+KCI+3H_{2}O



A mixture of ideal gases is cooled up to liquid helium temperature (4.22 K) to from an ideal solution. Is this statement true or false? Answer '1' or true and '2' for false.



50\ mL if a mixture of CO and H_{2} gave 20\ mL of CO_{2} after combustion in excess of air. Determine the percentage of CO by volume in the mixture.



The vapour pressure of an aqueous solution of cane sugar (mol. wt\ 342 ) is 756\ mm at 100^{o}C. How many grams of sugar are present per 1000\ g of water?
Give your answer in nearest integer.



What approximate proportions by volumes of water (d=1\ g/cc)  and ethylene glycol C_{2}H_{6}O_{2}(d=1.12\ g/cc) must be mixed ot ensure protection of an automobile cooling system to -10^{o}C?



A solution containing ethyl alcohol and propyl alcohol has a vapour pressure of 290\ mm at 30^{o}C. Find the vapour pressure of pure ethyl alcohol if its mole fraction in the solution is 0.65. The vapour pressure of propyl alcohol is 210\ mm at the same temperature.



Benzene and toluene fomr nearly ideal solution. If at 27^{o}C the vapour pressures of pure toluene and pure benzene are 32.06\ mm and 103.01\ mm respectively.
Calculate the vapour pressure of a solution containing 0.60 mole fraction of toluene.



10.03g of vinegar was diluted to 100mL and a 25mL sample was titrated with the 0.0176M Ba{(OH)}_{2} solution 34.30mL was required for equivalence. What is the percentage of acetic acid in the vinegar?



Igniting MnO_{2} converts it quantitatively to Mn_{3}O_{4}. A sample of pyrolusite is of the following composition: MnO_{2}= 80\%; SiO_{2} and other inert constituents 15\% and rest being water.
The sample is ignited in air to constant weight. What is the percentage of Mn in the ignited sample?

[Mn=54.9, O=16]



An alloy of aluminium and copper was treated with aqueous HCl The aluminium dissolved according to the reaction .
      \displaystyle Al + 3H^{+} \rightarrow Al^{+3} + \dfrac{3}{2}H_2 ,  
but the copper remained as pure metal . A 0.350-g sample of the alloy gave 415 cc of H_2 measured at 273 K and 1 \,atm pressure . What is the weight percentage of Al in the alloy ?
Give your answer as nearest integer.



Concentrated HCl solution is 37.0% HCl and has a density of 1.19g/mL. A dilute solution of HCl is prepared by diluting 4.50mL of this concentrated HCl solution to 100mL with water. Then 10mL of this dilute HCl solution reacts with an Ag{NO}_{3} solution. Calculate the volume of 0.108M Ag{NO}_{3} solution required to  precipitate all the chloride as AgCl(s)



Twenty grams of HI is heated at 327^0C in a bulb of 1-litre capacity. Calculate the volume percentage of H_2, \ I_2 and HI at equilibrium. Given that the mass law constant for the equation 2HI \rightleftharpoons H_2 + I_2 is 0.0559 at 327^0C when concentrations are expressed in moles / litre. 



The vapour pressure of water is 3167.2 Pa at 25^oC. What would be the vapour pressure of a solution of sucrose(with mole fraction of sucrose=0.1) and of a solution of levulose(with mole fraction of levulose=0.1)?



Liquid A and B form ideal solution over the entire range of composition. At temperature T, equimolar binary solution of liquids A and B has vapour pressure 45\ torr. At the same temperature, a new solution of A and B having mole fraction x_{A} and x_{B}, respectively, has a vapour pressure of 22.5\ torr. The value of x_{A}/x_{B} in the new solution is .....
\mathrm{(P^0_A= 20 torr)}



An aqueous solution freezes at 271.5 K. Determine its boiling point and vapour pressure at 298K. The cryoscopic constant of water is 1.86^oC/m, its ebullioscopic constant is 0.516^oC/m and the water vapour pressure at 298K is 3168 Pa.



What weight of the nonvolatile solute, urea (NH_2-CO-NH_2) needs to be dissolved in 100g of water in order to decrease the vapor pressure of water by 25\%? What will be the molality of the solution?



What are the concentration and percentage of Ag^+ ion remaining after Ag_2CrO_4 precipitates when 25 mL of 0.10M AgNO_3 is added to 25 mL of 0.10M K_2CrO_4? K_{sp}(Ag_2CrO_4)=1.1\times 10^{-12}.



The vapour pressure of pure water at 25^{o}C is 23.62\ mmHg. What will be the vapour pressure of a solution of 1.5\ g of urea in 50\ g is water?



The vapour pressure of a 0.01\ m solution of a weak base BOH in water at 20^{o}C is 17.536\ mm. Calculate K_{b} for the base. Aq. tension at 20^{o}C=17.54\ mm.

Then apply i=1+x and K_{b}=\dfrac{0.01 x^{2}}{1-x}



The rate of diffusion of a sample of ozonised oxygen is 0.98 times more than that of pure oxygen. Find the percentage (by volume) of ozone in the ozonised sample.



Assume liquefied petroleum gas (LPG) is a 50-50 (by mole) mixture of n -pentane and n-butane . calculate the calorific value (in kJ /mol) of gas available from a newly filled cylinder .give your answer divided by 100.

n-butane , C_4 H_{10} n-pentane , C_5 H_{12}
Vapour pressure 1800 Torr600 Torr
Calorific value2800 kJ /mol3600kJ /mol



A space capsule is filled with neon gas at 1 atm and 290K. The gas effuses through a pinhole into outer space at such a rate that the pressure drops by 0.3 mm/second. If the capsule were filled with 30\% He, 20\% O_2 and 50\% N_2(mole \%) at a total pressure of 1 atm and a temperature of 290K, calculate the rate of pressure drop.



A solution A (l) and B (l) with 30 mole percent of A is in equilibrium with its vapour which contains 60 mole percent of A . Assuming ideality of the solution and its vapour calculate the ratio of vapour pressure of pure A to that of pure B. (report your answer as ratio \times 2 )



Calculate the freezing point depression expected for 0.0711 \, m aqueous solution of Na_2SO_4 . If this solution actually freezes at -0.320^{\circ}\,C , what would be the value of van't Hoff factor? 
(K_f for water is 1.86 \,K \, kg \, mol^{-1}



What do you mean by 10 % aqueous solution of sodium carbonate? 



Define van't Hoff factor. 



Define the following terms : 
Van't Hoff factor (i) 



What do you understand by 'colligative properties'? 



What is the van't Hoff factor for a compound which undergo dimerisation in an organic solvent? 



What is collodion?



The dissolution of ammonia chloride in water is an endothermic process but still dissolves in water readily. Why? 



Give Reasons for the Following:
Why is it said that solubility of any solute changes with a change in temperature?



Which of the liquids in each of the following pair has higher vapour pressure: Mercury, water



How many types of solutions are formed? Write briefly about each type with an example.



Which of the liquids in each of the following pair has higher vapour pressure : Petrol, kerosene



Give reason for the following :
Blue solution of copper sulphate changes to green when a piece of iron is added to this solution.



A solution of A and B with 30 mole percent of A is in equilibrium with its vapour which contain 60 mole percent of A. Assuming that the solution and the vapour behave ideally, calculated the ratio of the vapour pressures of pure A and pure B.



(a) Benzoic acid completely dimerises in benzene. What will be the vapour pressure of a solution containing 61g of benzoic acid per 500g benzene when the vapour pressure of pure benzene at the temperature of the experiment is 66.6 torr?
(b) What would have been the vapour pressure is the absence of dimerisation?



Define the terms 'Vapour pressure and 'Solubility'.



Class 12 Engineering Chemistry Extra Questions