Solutions

Considering acetic acid dissociates in water, its dissociation constant is 6.25 10-5. If 5 mL of acetic acid is dissolved in 1 litre water, the solution will freeze at -x 10-2 C, provided pure water freezes at 0 C. x = . (Nearest integer) Given : (Kf)water = 1.86 K kg mol-1 density of acetic acid is 1.2 g mL-1. molar mass of water = 18 g mol-1. molar mass of acetic acid = 60 g mol-1. density of water = 1 g cm-3 Acetic acid dissociates as CH3COOH CH3COO + H

2.5 g of a non-volatile, non-electrolyte is dissolved in 100 g of water at 25 . The solution showed a boiling point elevation by 2 . Assuming the solute concentration is negligible with respect to the solvent concentration, the vapor pressure of the resulting aqueous solution is mm of Hg (nearest integer) [Given : Molal boiling point elevation constant of water (Kb) = 0.52 K kg mol-1, 1 atm pressure = 760 mm of Hg, molar mass of water = 18 g mol-1]

2.7 kg of each of water and acetic acid are mixed. The freezing point of the solution will be -x C. Consider the acetic acid does not dimerise in water, nor dissociates in water. x = (nearest integer) [Given: Molar mass of water = 18 g mol-1, acetic acid = 60 g mol-1 Kf H2O : 1.86 K kg mol-1 Kf acetic acid: 3.90 K kg mol-1 freezing point: H2O = 273 K, acetic acid = 290 K]

We have three aqueous solutions of NaCl labelled as 'A', 'B' and 'C' with concentration 0.1 M, 0.01 M and 0.001 M, respectively. The value of van 't Hoff factor (i) for these solutions will be in the order :

1. iA < iC < iB
2. iA < iB < iC
3. iA > iB > iC
4. iA = iB = iC

Mass of ethylene glycol (antifreeze) to be added to 18.6 kg of water to protect the freezing point at -24 is kg (Molar mass in g mol-1 for ethylene glycol 62, Kf of water = 1.86 K kg mol-1)

Identify the mixture that shows positive deviations from Raoult's Law

1. (CH3)2CO + CS2
2. (CH3)2CO + C6H5NH2
3. CHCl3 + C6H6
4. CHCl3 + (CH3)2CO

What happens to freezing point of benzene when small quantity of naphthalene is added to benzene?

1. Increases
2. Decreases
3. Remains unchanged
4. First decreases and then increases

The solution from the following with highest depression in freezing point/lowest freezing point is

1. 180 g of acetic acid dissolved in benzene
2. 180 g of acetic acid dissolved in water
3. 180 g of benzoic acid dissolved in benzene
4. 180 g of glucose dissolved in water

If a substance 'A' dissolves in solution of a mixture of 'B' and 'C' with their respective number of moles as nA, nB and nC. Mole fraction of C in the solution is

1. nCnA nB nC
2. nBnA+nB
3. nCnA+nB+nC
4. nCnA-nB-nC

The osmotic pressure of a dilute solution is 7 105 Pa at 273 K. Osmotic pressure of the same solution at 283 K is 104 Nm-2.