The pH of buffer solution containing 4 × 10^-3 and 0.4 moles of acetic acid (pK_a = 4.76) and sodium acetate respectively will be

In the mixture obtained by mixing 25.0 mL × 1.2 × 10^-3 MMnCl₂ and 35.0 mL of 6.0 × 10^-4 M KCl solution, the concentration (M) of Mn²⁺, K⁺ and CI^- ions respectively are

A. 6.0 × 10^-4, 3.0 × 10^-4, 1.5 × 10^-3

B. 6.0 × 10^-4, 3.0 × 10^-4, 9 × 10^-4

C. 5.0 × 10^-4, 3.5 × 10^-4, 13.5 × 10^-3

D. 5.0 × 10^-4, 3.5 × 10^-4, 8.5 × 10^-4

An aqueous solution containing m moles of non-volatile solute freezes at -0.186°C. The elevation in the boiling point of the same aqueous solution (K_f = 1.86°, K_b = 0.512°) would be

A. 0.186

B. 0.512

C. 0.0512

D. 0.51/1.86

Among the following, the equilibrium which is not affected by an increase in pressure is

A. 2SO₃(g) $$ \rightleftharpoons $$ 2SO₂(g) + O₂(g)

B. H₂(g) + l₂(s) $$ \rightleftharpoons $$ 2HI(g)

C. C(s) + H₂O(g) $$ \rightleftharpoons $$ CO(g) + H₂(g)

D. 3Fe(s) + 4H₂O(g) $$ \rightleftharpoons $$ Fe₃O₄(s) + 4H₂(g)

The number of degrees of freedom for a system consisting of NaCl(s), Na⁺ (aq) and Cl^- (aq) at equilibrium is

A. 2

B. 3

C. 4

D. 5