Previous year questions with solutions · 2024 – 2026
| Year | Questions | Papers | Avg / paper | Weightage |
|---|---|---|---|---|
| 2026 | 23 | 19 | 1.2 | 4.84% ▼ 4.2% vs last year |
| 2025 | 24 | 19 | 1.3 | 5.05% ▲ 38% vs last year |
| 2024 | 22 | 21 | 1 | 3.66% |
Which of the following statements are not correct? Choose the correct answer from the options given below :
19.5 g of fluoro acetic acid (molar mass = 78 g mol-1) is dissolved in 500 g of water at 298 K. The depression in the freezing point of water was 1°C. What is Ka of fluoro acetic acid ? (For water, Kf = 1.86 K kg mol-1). Assume molarity and molality to have same values.
'W' g of a non-volatile electrolyte solid solute of molar mass 'M' g mol-1 when dissolved in 100 mL water, decreases vapour pressure of water from 640 mm Hg to 600 mm Hg. If aqueous solution of the electrolyte boils at 375 K and Kb for water is 0.52 K kg mol-1, then the mole fraction of the electrolyte solute (x2) in the solution can be expressed as (Given : density of water = 1 g/mL and boiling point of water = 373 K)
HA(aq) H+(aq) + A-(aq) The freezing point depression of a 0.1 m aqueous solution of a monobasic weak acid HA is 0.20 C. The dissociation constant for the acid is Given: Kf(H2O) = 1.8 K kg mol-1, molality ≡ molarity
The percentage dissociation of a salt (MX3) solution at given temperature (van't Hoff factor i = 2) is % (Nearest integer)
1.24 g of AX2 (molar mass 124 g mol-1) is dissolved in 1 kg of water to form a solution with boiling point of 100.0156°C, while 25.4 g of AY2 (molar mass 250 g mol-1) in 2 kg of water constitutes a solution with a boiling point of 100.0260°C. Kb(H2O) = 0.52 kg mol-1 Which of the following is correct?
If A2B is 30% ionised in an aqueous solution, then the value of van't Hoff factor (i) is 10-1.
The observed and normal molar masses of compound MX2 are 65.6 and 164 respectively. The percent degree of ionisation of MX2 is %. (Nearest integer)
CrCl3 xNH3 can exist as a complex. 0.1 molal aqueous solution of this complex shows a depression in freezing point of 0.558 C. Assuming 100% ionisation of this complex and coordination number of Cr is 6, the complex will be (Given Kf = 1.86 K kg mol-1)
Arrange the following solutions in order of their increasing boiling points. (i) 10-4 M NaCl (ii) 10-4 M Urea (iii) 10-3 M NaCl (iv) 10-2 M NaCl
A solution containing 10 g of an electrolyte AB2 in 100 g of water boils at 100.52°C. The degree of ionization of the electrolyte ( ) is 10-1. (nearest integer) [Given : Molar mass of AB2 = 200 g mol-1, Kb (molal boiling point elevation const. of water) = 0.52 K kg mol-1, boiling point of water = 100°C; AB2 ionises as AB2 A2+ + 2B-]
Consider the dissociation of the weak acid HX as given below HX(aq) H+(aq) + X-(aq), Ka = 1.2 10-5 [Ka : dissociation constant] The osmotic pressure of 0.03 M aqueous solution of HX at 300 K is 10-2 bar (nearest integer). [Given : R = 0.083 L bar mol-1 K-1]
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
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 :
The solution from the following with highest depression in freezing point/lowest freezing point is