The partial pressure of ethane over a solution containing 6.56 × 10^–2 g of ethane is 1 bar. If the solution contains 5.00 × 10^–2 g of ethane, the partial pressure of the gas will be:

1. 0.66 bar

2. 0.96 bar

3. 0.76 bar

4. 0.19 bar

The positive deviations from Raoult’s law mean the vapour pressure is:

1. Higher than expected.
2. Lower than expected.
3. As expected.
4. None of the above

The vapour pressure of 1 molal solution of a non-volatile solute in water at 300 K would be:

(The vapour pressure of water at 300 K = 12.3 kPa)

A solution containing 30 g of non-volatile solute in 90 g of water has a vapour pressure of 2.8 kPa at 298 K. Further, 18 g of water is then added to the solution and the new vapour pressure becomes 2.9 kPa at 298 K. The vapour pressure of water at 298 K will be -

1) 1.53 kPa

2) 2.53 kPa

3) 3.53 kPa

4) 4.53 kPa

Two elements A and B form compounds having formula AB₂ and AB₄. When dissolved in 20 g of benzene (C₆H₆), 1 g of AB₂ lowers the freezing point by 2.3 K whereas 1.0 g of AB₄ lowers it by 1.3 K. The atomic masses of A and B are respectively:

(K_f for benzene is 5.1 K kg mol^-1)

1. 15.59 u and 52.64 u

2. 25.59 u and 42.64 u

3. 13.59 u and 52.64 u

4. 23.59 u and 32.64 u

The type of inter-molecular interactions present in:

The insoluble compound in water is /are:

1. Phenol

2. Formic acid and toluene

3. Phenol and toluene 

4. Toluene and chloroform

The mass percentage of aspirin (C₉H₈O₄) in acetonitrile (CH₃CN) when 6.5 g of C₉H₈O₄ is dissolved in 450 g of CH₃CN will be:
1. 1.424%
2. 4.424%
3. 5.124%
4. 2.124%

Nalorphene (C₁₉H₂₁NO₃), similar to morphine, is used to combat withdrawal symptoms in narcotic users. The dose of nalorphene generally given is 1.5 mg.

Calculate the mass of 1.5 × 10⁻³m aqueous solution required for the above dose.
1. 13.22 g
2. 3.22 g
3. 11.22 g
4. 9.22 g

The amount of benzoic acid (C₆H₅COOH) required for preparing 250 mL of 0.15 M solution in methanol is: