CBSE Questions for Class 12 Engineering Chemistry Solutions Quiz 13 - MCQExams.com

The vapour pressure of the solution of $$5\,g$$ on non-electrolyte in $$100\,g$$ of water at a particular temperature is $$2950\,N/{m^2}$$. The vapour pressure of water is $$3000\,N/{m^2}$$. The mocular mass of the solute is ?
  • $$54$$
  • $$124$$
  • $$180$$
  • $$340$$
The Vant Hoff factor for a dilute solution $${K_3}\left[ {Fe{{\left( {CN} \right)}_6}} \right]$$
  • 10
  • 4
  • 5
  • 0.25
50 mL of 1 M oxalic acid(molar mass = 126 g) is shaken with 0.5 g of wood charcoal, the final concentration of the solution after adsorption is 0.5 M. Calculate the amount of oxalic acid adsorbed per gram of charcoal.
  • 6.1
  • 6.2
  • 6.4
  • 6.3
Benzoic undergoes dimerization in benzene solution. The van't Hoff factor is related to the degree of association 'x' of the acid is ?
  • $${\text{i}} = \left( {1 - x} \right)$$
  • $${\text{i}} = \left( {1 + x} \right)$$
  • $${\text{i}} = \left( {1 - \frac{x}{2}} \right)$$
  • $${\text{i}} = \left( {1 + \frac{x}{2}} \right)$$
Which of the following solutions will have the lowest vapour pressure?
  • $$0.1 M\  Glucose$$
  • $$0.1 M\  NaCl$$
  • $$0.1 M\  BaCl_2$$
  • $$0.1 M Al_2 (SO_4)_3$$
Vapour Pressure of methyl alcohol and ethyl alcohol solution is represented by $$P=115{ x }_{ A}+140$$. Where $${ x }_{ A }$$ is the mole fraction of methyl alcohol. The value of $$\lim _{ { x }_{ A }\rightarrow 0 }{ \frac { { P }_{ B }^{ 0 } }{ { x }_{ B } }  } \\  $$
  • 255
  • 115
  • 140
  • 135
The vapour pressure of $$1$$ molal glucose solution at $$100^{o}C$$ will be 
  • $$760\ mmHg$$
  • $$76.0\ mmHg$$
  • $$1\ atm$$
  • $$746.32\ mmHg$$
At a certain temperature pure liquid A and liquid B have vapour pressures 10 torr and 37 torr respectively. For a certain ideal solution of A and B, the vapour in equilibrium with the liquid has the components A and B in the partial pressure ratio $$P_A : P_B=1 : 7 $$. What is the mole fraction of A in the solution? 
  • 0.346
  • 0.654
  • 0.5
  • None of these
Vapour pressure increase with increase in : 
  • Concentration of solution containing non-volatile soulute
  • Temperature up to boiling point
  • Temperature upto triple point
  • Altitude of the concerned place of boiling
Vapour pressure of pure 'A' is 70 mm of Hg at $$25^0C$$ it forms an ideal solution is with 'B' in which mole fraction of A is 0.If the vapour pressure of the solution is 84 mm is Hg at $$25^0C$$, the vapour pressure of pure 'B' at $$25^0C$$ is :
  • 56 mm Hg
  • 70 mm Hg
  • 140 mm Hg
  • 28 mm Hg
A mixture of  $$H_2SO_4$$  and $$H_2C_2O_4$$ (oxalic acid) and some inert impurity weighing 3.185g was dissolved in water and the solution was made up to 1litre. 10mL of this solution required 3mL of 0.1N $$NaOH$$ for complete neutralization. In another experiment, 100mL of the same solution in hot conditions requires 4mL of 0.02M $$KMnO_4$$ solution for complete reaction.
The weight % of $$H_2SO_4$$ in the mixture was:-
  • 40
  • 50
  • 60
  • 80
The mass of a non-volatile non-electrolyte solute (molar mass$$=50\ g\ mol^ {-1}$$) needed to be dissolved in $$114\ g$$ octane to reduce its vapour pressure to $$75\%$$ is:
  • $$37.5\ g$$
  • $$75\ g$$
  • $$150\ g$$
  • $$50\ g$$
At a certain temperature, the vapour pressure of water is $$50\ mm.$$ The relative lowering of vapour pressure of a solution containing $$36\ g$$ of glucose in $$900\ g$$ of water is
  • $$0.1$$
  • $$0.5$$
  • $$0.004$$
  • $$3.75$$

The possible van't Hoff factor for sodium chloride in water assuming sodium chloride is partially ionized:
  • $$0.5$$
  • $$0.75$$
  • $$2.5$$
  • $$1.5$$
Which of the following have least vapour pressure?
  • $$0.1\ M\ NaCl\ sol$$
  • $$0.1\ M\ urea\ sol$$
  • $$0.1\ M\ AlCl_{3}\ sol$$
  • $$0.1\ M\ KCl\ sol$$
$$K_2HgI_4$$ is $$40 \%$$ ionised in aqueous solution. The value of its van't Hoff factor (i) is:
  • $$1.8$$
  • $$2.2$$
  • $$2.0$$
  • $$1.6$$
The lowering of vapour pressure of 0.1 M aqueous solutions of $$NaCl,\  CuS{O_4}$$ and $${K_2}S{O_4}$$ are ;
  • all equal
  • in the ratio of 1 : 1 : 1.5
  • in the ratio of 3 : 2 : 1
  • in the ratio of 1.5 : 1 : 2.5
When a solution containing non-volatile solute is diluted with water,
  • its vapour pressure increases
  • its osmotic pressure increases
  • its boiling point increases
  • its freezing point increases
An ideal solution formed by mixing two liquids  'A' and 'B' find the pressure at which $${X_A} = {Y_B}\ ({P_A}^0 = 400\ torr,{P_B}^0 = 100\,torr)$$ 

$$({X_A}$$ and $${Y_B}$$ are mole fraction of A and B in liquid and vapour forms respectively at equilibrium.)
  • 250 torr
  • 200 torr
  • 150 torr
  • 125 torr
An ideal solution is formed by mixing two liquids 'A' and 'B'. Find pressure at which $${X_A} = {Y_B}\,\,({P_A}^\circ  = 400\,\,torr,\,\,{P_B}^\circ  = 100\,\,torr)\,\,:\,\,({X_A}\,\,and\,\,{Y_B}$$ are mole fractions of A and B liquids and vapour forms, respectively, at equilibrium.) 
  • 250 torr
  • 200 torr
  • 150 torr
  • 125 torr
At $${35}^{o}C$$, the vapour pressure of $$CS_2$$ is $$512mm$$ $$Hg$$, and acetone is $$344mm$$ $$Hg$$. A solution of $$CS_2$$ and acetone in, which the mol fraction of $$CS_2$$ is $$0.25$$, has a total vapour pressure of $$600mm$$ $$Hg$$. Which of the following statements is/are correct:
  • A mixture of $$100mL$$ of acetone and $$100mL$$ $$CS_2$$ of has a volume is $$200mL$$
  • When acetone and $$CS_2$$ are mixed at $${35}^{o}C$$, heat must be absorbed in order to produce a solution at $${35}^{o}C$$
  • When acetone and $$CS_2$$ are mixed at $${35}^{o}C$$, heat is released
  • There is negative deviation from Raoult's law
The Van't Hoff factor of 0.1 M $${\text{Ba}}{\left( {{\text{N}}{{\text{O}}_3}} \right)_2}$$ solutions is 2.The degree of dissociation will be  
  • 91.3%
  • 87%
  • 100%
  • 74%
A solution is prepared by mixing $${\text{8}}{\text{.5}}\,{\text{g}}$$ of $${\text{C}}{{\text{H}}_{\text{2}}}{\text{C}}{{\text{l}}_2}$$ and $$11.95\,{\text{g}}$$ of $${\text{CHC}}{{\text{l}}_{\text{3}}}$$. If vapour pressure of $${\text{C}}{{\text{H}}_{\text{2}}}{\text{C}}{{\text{l}}_{\text{2}}}$$ and $${\text{CHC}}{{\text{l}}_3}$$ at $${\text{298}}\,{\text{K}}$$ are $$415$$ and $$200\,{\text{mm}}$$ Hg respecetively, then mole fraction of $${\text{CHC}}{{\text{l}}_{\text{3}}}$$ in vapour form is:
  • $$0.162$$
  • $$0.675$$
  • $$0.325$$
  • $$0.486$$
A $$10\%$$ solution of $$NaCl$$ means that in $$100g$$ of solution there is:
  • $$5.85g\ NaCl$$
  • $$58.5g\ NaCl$$
  • $$10g\ NaCl$$
  • $$94g\ NaCl$$
The value of observed and calculated molecular weight of silver nitrate are $$92.64$$ and 170 respectively. The degree of dissociation of silver nitrate is :
  • $$60\%$$
  • $$83.5\%$$
  • $$46.7\%$$
  • $$60.23\%$$
Binary solute $$(AB)$$ $$60\%$$ dissociate and $$40\%$$   dimerise. Value of van't Hoff factor $$(i)$$ is 
  • $$1.20$$
  • $$1.10$$
  • $$1.40$$
  • $$1.50$$
Binary solute (AB) 60 % dissociate and 40 % dimerise. Value of van't Hoff factor (i) is 
  • 1.20
  • 1.10
  • 1.40
  • 1.50
Which of the following pairs do not form ideal solution
  • $${{\text{C}}_6}{{\text{H}}_6}\;and\;{\text{CC}}{{\text{l}}_4}$$
  • $${{\text{C}}_6}{{\text{H}}_6}\;{\text{and}}\;{{\text{C}}_6}{{\text{H}}_5}{\text{CH}}$$
  • $${{\text{C}}_2}{{\text{H}}_5}Br\;and\;{{\text{C}}_2}{{\text{H}}_5}{\text{l}}$$
  • none.
The relative lowering of vapour pressure of a solution of 6 g of urea dissolved  in 90 g of water is equal to 
  • 0.02
  • 0.04
  • 0.60
  • 0.03
The lowering of vapour pressure of a solvent by addition of a non-volatile solute to it is directly proportional to :
  • The strength of the solution
  • The nature of the solute in the solution
  • The atmospheric pressure
  • All

Two liquids A and B form ideal solution.At 300K,the vapour pressure of solution containing 1 mol of A and 3 mol of B is 550mm Hg.At the same temperature,if one more mole of B is added to this solution,the vapour pressure of the solution increases by 10mm Hg.Determine the vapour pressures of A and B in their pure states.
  • $$563$$ and $$469$$
  • $$500$$ adn $$1250$$
  • $$513$$ and $$494$$
  • $$400$$ and $$600$$
The vapour pressure of water at T(K) is 20 mm Hg. The following solutions are prepared at T(K) :
  • 6 g of urea (mol. wt. = 60) is dissolved in 178.2 g of water
  • 0.01 mole of glucose is dissolved in 179.82 g of water
  • 5.3 g of $$N{a_2}C{O_3}$$ (mol. wt. =106) is dissolved in 179.1 g of water.
  • non of these
If $${X_A}$$ and $${X_B}$$ represent mole fraction in liquid phase while $${y_A}$$ and $${y_B}$$ represent mole fraction in vapour phase in binary solution. Which of the following statements is/are correct?
1381655_f5557fc0e17c4560bf23baf8342ccdd0.PNG
  • At point C liquid and vapour phase have same composition
  • Vapour pressure of B is less than A
  • Intermolecular forces in the solution are weaker than between like particles
  • All of these
Solubility will be higher when the process is exothermic.
  • True
  • False
Molar volume of liquid A (d=0.8 gm/ml) increase by a factor of 2000 when it vapourises at 2000K. The vapour pressure of liquid A at 200K is:
 [R=0.08 L-atm/mol-K] (Molar mass of A=80 g/mol)
  • 0.4 atm
  • 8 atm
  • 0.8 atm
  • 0.08 atm
In the accompanied diagram, the ideal behaviour of a solution is shown by the line/s
1385348_b32911c3a5df40e482db70b2aba313d9.PNG
  • AD
  • CB
  • BD
  • AD,CB 
An ideal solution contains two volatile liquids $$A (P^0=100 \ torr)$$. If the mixture contains 1 mole of A and 3 moles of B, the total vapour pressure of distillate is:
  • 150 torr
  • 188.88 torr
  • 185.72 torr
  • 198.88 torr
Which of the following mixture will be producing acidic solution at $$25^ {o}C$$?
  • $$200ml\dfrac {M}{10}H_{2}SO_{4}+300ml\dfrac {M}{10}NaOH$$
  • $$600ml\dfrac {M}{10}HNO_{3}+400ml\dfrac {M}{10}NaOH$$
  • $$900ml\dfrac {M}{10}HCI+300ml\dfrac {M}{10}NaOH$$
  • $$All\ of\ these$$
Concentrated aqueous sulphuric acid is $$98% { H }_{ 2 }{ SO }_{ 4 }$$ by mass and has a density of $$1.80{ gmL }^{ -1 }.$$ Volume of acid required to make one lite of $$0.1 M{ H }_{ 2 }{ SO }_{ 4 }$$ solution is:
  • 11.10 mL
  • 16.65 mL
  • 22.20 mL
  • 5.55 ml
A vessel of volume $$V = 16.62$$ litres contains a mixture of hydrogen and helium at a temperature of 27$$^{0}$$C and pressure 6 atmosphere.The mass of the mixture is 10 g. Then 
The ratio of mass of hydrogen to that of helium will be :
  • 1 /2
  • 2 /3
  • 3 / 2
  • 4 / 3
For  binary ideal liquid solution, the total pressure of the solution is given as :
  • $${{\text{P}}_{{\text{total}}\;}} = {\text{P}}_{\text{A}}^{\text{o}}{\text{ + }}\left( {{\text{P}}_{\text{A}}^{\text{o}} - \;{\text{P}}_{\text{B}}^{\text{o}}} \right){{\text{X}}_{\text{B}}}$$
  • $${{\text{P}}_{{\text{total}}\;}} = {\text{P}}_B^{\text{o}}{\text{ + }}\left( {{\text{P}}_{\text{A}}^{\text{o}} - \;{\text{P}}_{\text{B}}^{\text{o}}} \right){{\text{X}}_A}$$
  • $${{\text{P}}_{{\text{total}}\;}} = {\text{P}}_B^{\text{o}}{\text{ + }}\left( {{\text{P}}_B^{\text{o}} - \;{\text{P}}_A^{\text{o}}} \right){{\text{X}}_A}$$
  • $${{\text{P}}_{{\text{total}}\;}} = {\text{P}}_{\text{B}}^{\text{o}}{\text{ + }}\left( {{\text{P}}_B^{\text{o}} - \;{\text{P}}_A^{\text{o}}} \right){{\text{X}}_B}$$
To an aqueous solution of $$NaI$$, increasing amounts of solid $$HgI_ { 2 }$$ is added, the vapour pressure of the solution:
  • decreases to a constant value
  • increases to a constant value
  • increases first and then decreases
  • remains constant because $$\mathrm { HgI} _ { 2 }$$ is sparingly soluble in water
The volume of 0.0168 mol of $${ O }_{ 2 }$$ obtained by decomposition of $${ KCIO }_{ 3 }$$ and collected by displacement of water is 428ml at a pressure of 754 mm Hg at $${ 25 }^{ 0 }C.$$ The pressure of water vapour at $${ 25 }^{ 0 }C$$ is:
  • 18 mm Hg
  • 20 mm Hg
  • 22 mm Hg
  • 24 mm Hg
Colligative properties of a dilute solution depend on
  • Nature of solute
  • Nature of solvent
  • Number of solute particles
  • Number of solvent particles
Two liquids A & B form an ideal solution. What is the vapour pressure of solution containing 2 moles of A and 3 moles of B at 300 K? [Given: At 300 K, Vapour pr. of pure liquid A $$\left( P\begin{matrix} 0 \\ A \end{matrix} \right) $$=100 torr, Vapour pr. of pure liquid B $$\left( P\begin{matrix} 0 \\ B \end{matrix} \right) $$=300 torr]
  • 200 torr
  • 140 torr
  • 180 torr
  • None of these
A mixture of $$CO$$ and $$CO_2$$ is found to have a density of 1.50 $$g L^{-1}$$ at 20$$^0C$$ & 740 mm pressure. Mole $$\%$$ of $$CO_2$$ in the given mixture is:
  • $$64.5$$%
  • $$56.2$$%
  • $$62.8$$%
  • $$45.6\%$$
Observe the following abbreviations, $$\pi _{obs}=$$  observed colligative property,  $$\pi_{cal} = $$ theoretical colligative property, assuming normal behaviour of solute. Van't Haff factor (i) is given by:
  • $$I= \pi_{obs}\times \pi_{cal}$$
  • $$I= \pi_{obs} + \pi_{cal}$$
  • $$I= \pi_{obs}-\pi_{cal}$$
  • $$\displaystyle I= \frac{\pi_{obs}}{\pi_{cal}}$$
Which of the following electrolytes has the same van't Hoff factor$$(i)$$ as that of aluminium sulphate:
  • $$N a _ { 3 } P O _ { 4 }$$
  • $$\mathrm { Hg } _ { 2 } \mathrm { Cl } _ { 2 }$$
  • $$K _ { 3 } \left[ F e ( \mathrm { CN } ) _ { 6 } \right]$$
  • $$K _ { 4 } \left[ F e ( C N ) _ { 6 } \right]$$
Which one of the following is incorrect for ideal solution ?
  • $$\Delta P=Pobs-{ P }_{ calculated} \quad by\quad Raoult's=0$$
  • $$\Delta { G }_{ mix }=0$$
  • $$\Delta { H }_{ mix }=0$$
  • $$\Delta U_{ mix }=0$$
Relative lowering in vapour pressure of a solution containing 1 mole $$K_{2}SO_{4}$$  in 54 g $$H_{2}O$$  is: ( $$K_{2}SO_{4}$$ is 100 % ionised ) 
  • $$\dfrac{1}{55}$$
  • $$\dfrac{3}{55}$$
  • $$\dfrac{3}{4}$$
  • $$\dfrac{1}{2}$$
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