Conjugate base of ${\mathrm{HSO}}_4^{-}$ is

• ${\mathrm{SO}}_4^{2-}$

• H₂SO₄

• ${\mathrm{H}}_3{\mathrm{SO}}_4^{+}$

• None of these

The pK_a of a weak acid is 4.8. What should be the ratio of $\frac{\left[\mathrm{acid}\right]}{\left[\mathrm{salt}\right]}$, if a buffer of pH = 5.8 is required?

• 0.1

• 10

• 1

• 2

Which of the following would produce a buffer solution when mixed in equal volumes?

• 1 M CH₃COOH and 0.5 M NaOH

• 1 M CH₃COOH and 0.5 M HCl

• 1 M NH₄OH and 0.5 M NaOH

• 1 M NH₄Cl and 0.5 M HCl

Equilibrium constant for the reaction,

H₂O (g) + CO (g) $\rightleftharpoons$H₂ (g) + CO₂ (g) is 81.

If velocity constant of the forward reaction is 162 L mol^-1s^-1. What is the velocity constant (in L mol^-1s^-1) for the backward reaction?

• 13122

• 2

• 261

• 243

185.

Which one of the following statements is correct with respect to basic character ?

• PH₃ > P(CH₃)₃

• PH₃ = NH₃

• PH₃ > NH₃

• P(CH₃)₃ > PH₃

75 mL of 0.2 M HCl is mixed with 25 mL of 1M HCl. To this solution, 300 mL of distilled water is added. What is the pH of the resultant solution?

• 1

• 2

• 4

• 0.2

If the ionic product of water (K_w) is 1.96 x 10^-14 at 35°C, what is its value at 10°C?

• 1.96 × 10^-14

• 3.92 × 10^-14

• 2.95  × 10^-14

• 1.96 × 10^-13

Which one of the following statements is correct?

• Bronsted-Lowery theory could not explain the acidic nature of BCl₃

• The pH of 0.01 M NaOH solution is 2.

• The ionic product of water at 25°C is 10^-10 mol²L^-2. 

• The pH of a solution can be calculated using the equation pH = log[H⁺].

One mole of A(g) is heated to 200°C in a one litre closed flask, till the following equilibrium is reached.

A(g) B(g)

The rate of forward reaction at equilibrium is 0.02 mol L^-1min^-1. What is the rate (in mol L-1min^-1) of the backward reaction at equilibrium?

• 0.04

• 0.01

• 0.02

• 1

Iron sulphide is heated in air to form A an oxide of sulphur. A is dissolved in water to give an acid. The basicity of this acid is

• 2

• 3

• 1

• zero