Raoult's Law

Q.

What is the formula of brine?

Q. In 1 L saturated solution of $AgCl\left[K_{sp}\right(AgCl)=1.6\times {10}^{-10}],$ 0.1 mole of $CuCl[K_{p\left(CuCl\right)}=1.0\times {10}^{-6}]$ is added. The resultant concentration of $A{g}^{+}$ in the solution is $1.6\times {10}^{-x}.$ The value of 'x' is ___

Q. Determine mole fraction of $C{H}_{3}OH$ in an aqueous solution of $C{H}_{3}OH$ whose molality is 2.00 m.

1. 0.35
2. 0.035
3. 0.65
4. 0.965

Q. Which of the following graph is valid for a solution containing phenol and aniline?
Assume that at the given constant temperature of solution, vapour pressure of phenol (A) in pure state is more than that of aniline (B) in pure state.

Q. If the density of a 3 M thiosulphate $\left(N{a}_2{S}_2{O}_3\right)$ solution is 1.2 g/mL, then the molality of the solution is:

1. 4.13 m
2. 2.57 m
3. 3.85 m
4. 5.46 m

Q.

The vapour pressure will be lowest for

1. 0.1 M sugar solution

2. 0.1 M KCl solution

3. 0.1 M Cu(NO₃)₂ solution

4. 0.1 M AgNO₃ solution

Q. The vapour pressures of pure liquids A and B are 400 and 600 mm Hg, respectively at 298 K. On mixing the two liquids, the sum of their initial volumes is equal to the volume of the final mixture. The mole fraction of liquid B is 0.5 in the mixture. The vapour pressure of the final solution, the mole fractions of components A and B in vapour phase, respectively are:

1. 500 mm Hg; 0.4, 0.6
2. 500 mm Hg; 0.5, 0.5
3. 450 mm Hg; 0.5, 0.5
4. 450 mm Hg; 0.4, 0.6

Q. Which of the following statement is correct for a solution containing binary mixture of volatile liquids?

Q. $\text{Vapour pressure of pure A,}\left(p_A^{\circ }\right)=100mmHg$
$\text{Vaour pressure of pure B,}\left(p_B^{\circ }\right)=150mmHg$
2 mol of liquid 'A' and 3 mol of liquid 'B' are mixed to form an ideal solution. The vapour pressure of solution will be :

1. $130mmHg$
2. $140mmHg$
3. $135mmHg$
4. $145mmHg$

Q. The vapour pressure of pure liquids 1 and 2 are $450mmHg$ and $700mmHg$ respectively at $350K$. At a point when total vapour pressure is $600mmHg$, choose the correct option(s) :

1. Mole fraction of component 2 in vapour phase is 0.3
2. Mole fraction of component 2 in vapour phase is 0.7
3. Mole fraction of component 1 in liquid phase is 0.4
4. Mole fraction of component 1 in liquid phase is 0.6

Q.

The vapour pressure of pure benzene and toluene are 160 and 60 torr respectively. The molefraction of toluene in vapour phase in contact with equimolar solution of benzene and toluene is

1. 0.50

2. 0.6

3. 0.27

4. 0.73

Q. Consider the following partially labelled figure for an ideal binary solution of benzene and toluene and answer the following questions:
What is $p_{\text{toluene}}^{\circ }\left({25}^{\circ }\text{C}\right)$?

1. $30\text{mm Hg}$
2. $100\text{mm Hg}$
3. $22\text{mm Hg}$
4. $40\text{mm Hg}$

Q.

The condition of Efflorescence

1. Vapour pressure of hydrated crystal < atmospheric vapour pressure

2. Vapour pressure of hydrated crystal ≤ atmospheric vapour pressure

3. Vapour pressure of hydrated crystal = atmospheric vapour pressure

4. Vapour pressure of hydrated crystal > atmospheric vapour pressure

Q. Benzene and toluene form nearly ideal solution At ${20}^{\circ }C,$ the vapour pressure of benzene is 75 torr and that of toluene is 22 torr. The partial vapour pressure of benzene at ${20}^{\circ }C$ for a solution containing 78 g of benzene and 46 g of toluene in torr is

1. 50
2. 25
3. 37.5
4. 53.5

Q.

For a solution of volatile liquids the partial vapour pressure of each component in solution is directly proportional to

1. Molarity

2. Mole fraction

3. Molality

4. Normality

Q. Two compounds A and B in when mixed form nearly ideal solutions. At room temperature, $P_A^0=40mmHg$ and $P_B^0=120mmHg$.
A liquid mixture is composed of $1mol$ of A and $3mol$ of B.
If the pressure over the mixture at room temperature is reduced. At what pressure does the first vapour form?

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

Q. Consider a binary mixture of two ideal volatile liquids A and B having vapour pressure of $400mmHg$ and $600mmHg$ in their pure state.
What will be the mole fraction of component A in vapour phase $\left(y_A\right)$ if the total pressure $\left(P_T\right)$ of the solution is $500mmHg$?

Q. The vapour pressure of ethanol (A) and methanol (B) are $44.5mmHg$ and $88.7mmHg$ respectively. An ideal solution is formed at the same temperature by mixing $60g$ of ethanol with $40g$ of methanol. Calculate the total vapour pressure of the solution $\left(P_T\right)$ and the mole fraction of methanol in the vapour phase $\left(Y_B\right)$

Q.

Equal volumes of 0.1M urea and 0.1M glucose are mixed. The mixture will have:

1. Same osmotic pressure

2. Lower osmotic pressure

3. Higher osmotic pressure

4. Cannot be predicted

Q.

An aqueous solution of sucrose (C₁₂H₂₂O₁₁) containing 34.2 g/L of sucrose has an osmotic pressure of 2.38 atm at 17° C. For an aqueous solution of glucose (C₆H₁₂O₆) to be isotonic with this solution, it's concentration (in g/L) should be:

1. 34.2 g/L

2. 17.1 g/L

3. 18.0 g/L

4. 36.0 g/L

Q. Which is incorrect about Henry's law

Q. Benzene and toluene form nearly ideal solutions. At ${20}^{\circ }$, the vapour pressure of benzene is 75 torr and that of toluene is 22 torr. The partial vapour pressure of benzene at ${20}^{\circ }$ for a solution containing 78g of benzene and 46g of toluene in torr is

1. 50
2. 25
3. 37.5
4. 53.5

Q.

KBr is 80% dissociated in solution. The freezing point of 0.5 molal solution is:

1. 273 K

2. 277 K

3. 271.326 K

4. 269 K

Q.

12 g of urea is dissolved in 1 litre of water and 68.4 g of sucrose is dissolved in 1 litre of water.The lowering of vapour pressure of the first case is:

1. Equal to second

2. Greater than second

3. Less than Second

4. Double that of second.

Q.

The pressure under which liquid and vapour can coexist at equilibrium is called the

1. Limiting vapour pressure
2. Real vapour pressure
3. Normal vapour pressure
4. Saturated vapour pressure

Q. A cylinder contains $0.9$ moles of benzene vapour and $0.1$ moles of toluene vapour at $50{}^{o}C$ . The pure vapour pressure of benzene liquid and the pure vapour pressure of toluene liquid at $50{}^o$C are 600 torr and 200 torr respectively.
What is the mole fraction of liquid benzene in the solution?

1. $0.25$
2. $0.75$
3. $0.50$
4. $0.90$

Q. Mole fraction of the component $A$ in vapour phase is $x_1$ and the mole fraction of component $A$ in liquid mixture is $x_2$. The total vapour pressure of liquid mixture is.
Here,
$p_A^{\circ }=$ vapour pressure of pure $A$
$p_B^{\circ }=$ vapour pressure of pure $B$

1. $\frac{p_B^{\circ }\times x_1}{x_2}$
2. $\frac{p_A^{\circ }\times x_1}{x_2}$
3. $\frac{p_B^{\circ }\times x_2}{x_1}$
4. $\frac{p_A^{\circ }\times x_2}{x_1}$

Q. Mixture(s) showing positive deviation from Raoult’s law at ${35}^{\circ }C$ is/are:

1. carbon tetrachloride + methanol
2. carbon disulphide + acetone
3. benzene + toluene
4. phenol + aniline

Q.

The vapour pressure of pure benzene and toluene are 160 and 60 torr respectively. The molefraction of toluene in vapour phase in contact with equimolar solution of benzene and toluene is

1. 0.50

2. 0.6

3. 0.27

4. 0.73