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CBSE Questions for Class 12 Engineering Chemistry Solutions Quiz 1 - MCQExams.com

When 200 g of an oleum sample labelled as 109% is mixed with 300 g of another oleum sample labelled as 118% the new labelling of resulting oleum sample becomes
  • 114.4%
  • 112.6%
  • 113.5%
  • 127%
A sample of oleum is labelled as 112%. In 200 g of this sample, 18 g water is added, The resulting solution will contain 
  • 218 g pure H2SO4
  • 218 g H2SO4 and 6 g free SO3
  • 212 g H2SO4 and 6 g free SO3
  • 191.33 g H2SO4 and 26.67 g free SO3
Vapour pressure of liquid 
  • increases with increase in temperature
  • decrease with increase in temperatuyre
  • is independent of temperature
  • either increases or decreases with the increase in temperature, depending on the nature of liquid
Which of the following behaviour is true about the ideal binary liquid solution of liquids A and B if P0A<P0B?
  • plot of Ptotal|vsXA in non linear
  • plot of Ptotal|vsXB is linear with +ve slope
  • plot of Ptotal|vsXB is linear with slope = 0
  • plot of Ptotal|vsXB is linear with -ve slope
Benzene and toulene from an ideal solution, the vapour pressures of the benzene and toluene are 75 mm and 25 mm respectively at 200C if the mole fractions of benzene and toluene in vapour are 0.75 and 0.25 respectively the vapour pressure of the ideal solution is 
  • 62.5 mm
  • 50 mm
  • 30 mm
  • 40 m
The vapour pressure of a soluiton of two liquids A ( P0=80mm,X=0.4) and B(P0=120mm,X=0.6) is found to be 100 mm, it shows that the solution exhibits

  • negative deviation from ideal behaviour
  • positive deviation from ideal behaviour
  • ideal behaviour
  • positive deviation at lower concentration
Heptane and octane from ideal solution at 373 K the vapour pressure of the pure liquids are 106 kPa and 46 kpa respectively . what will be the vapour pressure, in bar of mixture of 30.0 g of heptane and 34.2 g of octane ?
  • 76 bar
  • 152 bar
  • 1.52 bar
  • 0.76 bar
For an ideal solution of A and B , YA is the mole fraction of A in the vapour phase at equilibrium . which of the following plot should be linear ?
  • PtotalvsYA
  • PtotalvsYB
  • 1PtotalvsYA
  • 1Ptotalvs1YA
Under the condition of a similar temperature, which of the following solution will have, minimum vapour pressure?
  • 0.1 M sugar
  • 0.1 M NaCl
  • 0.1 m BaCl2
  • 0.1 M Al2(SO4)3
A mixture contains 1 mole of volatile liquid A(P0A=100mmHg) and 3 moles of volatile liquidB(P0B=80mmHg) if the solution behaves ideally, the total vapour pressure of the distillate is 
  • 85 mm Hg
  • 85.88 mm Hg
  • 90 mm Hg
  • 92 mm Hg
An aqueous solution of sucrose is 0.5 molal. What is the vapour pressure of water above this solution ? The vapour pressure of pure water is 25.0 mm Hg at this temperature.
  • 24.8 mm Hg
  • 0.45 mm Hg
  • 2.22 mm Hg
  • 20.3 mm Hg
A liquid mixture of A and B (assume ideal solution ) is placed in a cylinder and piston arrangement . The piston is slowly pulled out isothermally so that the volume of liquid decreases and that of vapour increases. at the instant when the quantity of the liquid still remaining is negligibly small, the mole fraction of 'A' in the vapour is 0.4 .If P0A=0.4atm,P0B=1.2atm at this temperature, the total pressure at which the liquid has almost evaporated is ?
  • 0.667 atm
  • 1.5 atm
  • 0.8 atm
  • 0.545 atm
Liquids A and B from an ideal solution. A certain solution of A and B contains 25 mole percent of A whereas the vapours in the equilibrium with the solution at 298 K contains 50 mole per cent of A. The ratio of vapour pressures of pure A to that of pure B at 298 K , is 
  • 1 :1
  • 3 : 1
  • 1 :3
  • 2 :1
The ratio between lowering of vapour pressure of solution and mole fraction of solute is equal to 
  • relative lowering of vapour pressure
  • vapour pressure of pure solvent
  • vapour pressure of solution
  • molar mass of solvent
For each of the following dilute solutions van't Hoffs factor is equal of 3 except
  • Na2SO4
  • CaF2
  • K3PO4
  • (NH4)2CO3
Liquids A and B from an ideal solution. the plot of 1XA(yaxis)vs1YA(xaxis) is linear whose slope and intercept , respectively, are given as
  • P0AP0B,P0AP0BP0B
  • P0AP0B,P0BP0AP0B
  • P0BP0A,P0AP0BP0B
  • P0BP0A,P0AP0BP0A
The limiting value of van't Hoff's factor for Na2SO4 is 
  • 2
  • 3
  • 4
  • 5
At what pressure half of the total moles of liquid solution will vaporize ?
  • 567.14 mm Hg
  • 63.25 mm Hg
  • 70 mm Hg
  • 66.67 mm Hg
If the pressure over the mixture at 300 K is reduced at what pressure does the first vapour form?
  • 40 mm Hg
  • 70 mm Hg
  • 100 Mm Hg
  • 199 mmHg
A liquid solution is formed by mixing 10 moles of anline and 20 moles of phenol at a temperature where the vapour phenol are 90 and 897 mm Hg, respectively . The possible vapour pressure of solution at that temperature is ?
  • 82 mm Hg
  • 88 mm Hg
  • 90 mm Hg
  • 94 mm Hg
If the pressure is reduced further, at what presure does the trace of liquid disppear?
  • 57.14 mm Hg
  • 40 Mm Hg
  • 100 mm Hg
  • 66.67 mm Hg
The vapour pressure of pure liquids A, B and C are 75, 22 and 10 torr , respectively. Which of the following is /are possible values of vapour pressure of binary or ternary solutions having equimolar amounts of these liquids? Assume ideal behaviour for all possible solutions
  • 53.5 torr
  • 35.67 torr
  • 48.5 torr
  • 16 torr
The vapour pressure of the solution this composition is:
  • P0A.P0B
  • (P0AP0B)
  • (P0A+P0B)
  • 0.5(P0A+P0B)
Which of the following is the only incorrect informarion regarding the composition of the system at 0.51 bar pressure ?
  • XA=0.45
  • YA=617
  • nA(liquid)=1211
  • nA(vapour)=1211
If the vapour are compressed slowly and isothermally , at what pressure , the first drop of liquid will appear ?
  • 0.4 bar
  • 0. 5 bar
  • 0.52 bar
  • 0.6 bar
In a binary electrolyte (AB type ) the observed lowering of vapour pressure as compared to the theorotically calculated one for non electrolyte can never be
  • more than double
  • exactly equal to double
  • less than double
  • more than one
One having high vapour pressure at temperature below its melting point is?
  • Benzoic acid
  • Salicylic acid
  • Citric acid
  • All of these
The vapour pressure of pure liquid A at 800C is
  • 807.4 mm
  • 511.1 mm
  • 755.6 mm
  • 533.3 mm
Two liquids A and B form an ideal solution. the solution has a vapor pressure of 700 torrs at 800C. it is distilled till 2/3rd of the solution is collected as condensate. the composition of the condensate xA=0.75. and that of residue is xA if the vapor pressure of the residue at 80^0 C is 600 torr. which of the following is/are true? 
  • The composition of the original liquid was x_A = 0.6
  • The composition of the original liquid was x_A = 0.4
  • P^0_A = \frac {2500}{3} Torr
  • P^0_B = 500 Torr
The reading of pressure gauge at which only liquid phase exists
  • 499
  • 399
  • 299
  • none
On mixing heptane and octane from an ideal solution. At 373 K, the vapour pressure of the two liquid compounds (heptane and octane) are 105\ kPa and 45\ kPa respectively. Vapour pressure of the solution obtained by mixing 250g of heptane and 35g of octane will be (molar mass of heptane =100 and octane =114\ g\ mol^{-1})
  • 72.0\ kPa
  • 36.1\ kPa
  • 98.4\ kPa
  • 114.5\ kPa
Which of the following is true when components forming an ideal solution are mixed?
  • \Delta H_m = \Delta V_m = 0
  • \Delta H_m > \Delta V_m
  • \Delta H_m < \Delta V_m
  • \Delta H_m = \Delta V_m = 1
Which pair from the following will not form an ideal solution?
  • CCl_4 + SiCl_4
  • H_2O + C_4H_9OH
  • C_2H_5Br + C_2H_5I
  • C_6H_{14} + C_7H_{16}
60 \,gm of Urea (Mol. wt 60) was dissolved in 9.9 moles of water. If the vapour pressure of pure water is P_0 , the vapour pressure of solution is
  • 0.10 \,P_0
  • 1.10 \,P_0
  • 0.90 \,P_0
  • 0.99 \,P_0
The vapour pressure lowering caused by the addition of 100 \,g of sucrose (molecular mass = 342) to 1000 \,g of water if the vapour pressure of pure water at 25 ^\circ C is 23.8 \,mm \,Hg
  • 1.25 \,mm \,Hg
  • 0.125 \,mm \,Hg
  • 1.15 \,mm \,Hg
  • 00.12 \,mm \,Hg
5 \,cm^3 of acetone is added to 100 \,cm^3 of water, the vapour pressure of water over the solution
  • It will be equal to the vapour pressure of pure water
  • It will be less than the vapour pressure of pure water
  • It will be greater than the vapour pressure of pure water
  • It will be very large
Which property is shown by an ideal solution
  • It forms Raoult's law
  • \Delta H_{mix} = 0
  • \Delta V_{mix} = 0
  • All of these
Which has maximum vapour pressure?
  • HI
  • HBr
  • HCl
  • HF
An example of near ideal solution is
  • n-heptane and n-hexane
  • CH_3COOH + C_5H_5N
  • CHCl_3 + (C_2H_5)_2O
  • H_2O + HNO_3
Vapour pressure of a solution is
  • Directly proportional to the mole fraction of the solvent
  • Inversely proportional to the mole fraction of the solute
  • Inversely proportional to the mole fraction of the solvent
  • Directly proportional to the mole fraction of the solute
Which of the following solution in water possesses the lowest vapour pressure?
  • 0.1 (M) NaCl
  • 0.1 (M) BaCl_2
  • 0.1 (M) KCl
  • None of these
Which of the following mixture shows positive deviation by ideal behaviour
  • CHCl_3 + (CH_3)_2CO
  • C_6H_6 + C_6H_5CH_3
  • H_2O + HCl
  • CCl_4 + CHCl_3
Which property is not found in ideal solution
  • P_A \neq P^0_A \times X_A
  • \Delta H_{mix} \neq 0
  • \Delta V_{mix} \neq 0
  • All of these
Two 5 molal solutions are prepared by dissolving a non-electrolyte non-volatile solute separately in the solvents X and Y. The molecular weights of the solvents are M_X and M_Y, respectively where M_X=\displaystyle\frac{3}{4}M_Y. The relative lowering of vapour pressure of the solution in X is "m" times that of the solution in Y. Given that the number of moles of solute is very small in comparison to that of solvent, the value of "m" is?
  • \displaystyle\frac{3}{4}
  • \displaystyle\frac{1}{2}
  • \displaystyle\frac{1}{4}
  • \displaystyle\frac{4}{3}
Two open beakers one containing a solvent and the other containing a mixture of that solvent with a non volatile solute are together sealed in a container. Over time:
  • The volume of the solution does not change and the volume of the solvent decreases
  • the volume of the solution deceases and the volume of the solvent increases
  • the volume of the solution and the solvent does not change
  • the volume of the solution increases and the volume of the solvent decreases
Liquid M and liquid N form an ideal solution. The vapour pressures of pure liquids M and N are 450 and 700\ mm Hg, respectively, at the same temperature. Then correct statement is:
({x}_{M}= Mole fraction of M in solution;
{x}_{N}= Mole fraction of N in solution;
{y}_{M}= Mole fraction of M in vapour phase;
{y}_{N}= Mole fraction of N in vapour phase)
  • ({x}_{M}-{y}_{M})< ({x}_{N}-{y}_{N})
  • \cfrac{{x}_{M}}{{x}_{N}}< \cfrac{{y}_{M}}{{y}_{N}}
  • \cfrac{{x}_{M}}{{x}_{N}}> \cfrac{{y}_{M}}{{y}_{N}}
  • \cfrac{{x}_{M}}{{x}_{N}}= \cfrac{{y}_{M}}{{y}_{N}}
Which one is not equal to zero for an ideal solution?
  • \Delta V_{mix}
  • \Delta P=P_{observed}-P_{Raoult}
  • \Delta H_{mix}
  • \Delta S_{mix}
Consider the following liquid - vapour equilibrium Liquid \rightleftharpoons Vapour. Which of the following relations is correct?
  • \dfrac {dlnG}{dT^{2}} = \dfrac {\Delta H_{v}}{RT^{2}}
  • \dfrac {dlnP}{dT} = \dfrac {-\Delta H_{v}}{RT}
  • \dfrac {dlnP}{dT^{2}} = \dfrac {-\Delta H_{v}}{T^{2}}
  • \dfrac {dlnP}{dT} = \dfrac {\Delta H_{v}}{RT^{2}}
For an ideal solution, the correct option is :
  • \Delta_{mix}S=0 at constant T and P
  • \Delta_{mix}V\neq 0 at correct T and P
  • \Delta_{mix}H=0 at constant T and P
  • \Delta_{mix} G=0 at constant T and P
The van't Hoff factor (i) for a dilute aqueous solution of the strong electrolyte barium hydroxide is :
  • 2
  • 3
  • 0
  • 1
0:0:2


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