Question

HX is a weak acid (Ka = 10^-5). It forms a salt NaX (0.1M) on reacting with caustic soda. The degree of hydrolysis of NaX is

Answer 1

Answer:

X- + H2O -à HX + OH-. Kh = Kw/ Ka = 10^(-9). Kh = Cα^2 = 10^(-9). Or α^2 = 10^(-8). Or, α = 10^(-4). Hence the % degree of dissociation = 10-4 x 100 = 0.01%. The degree of hydrolysis can be referred as the percentage or fraction of total salt that is hydrolysed at the equilibrium. Example, if 90% of any salt solution is hydrolysed, the degree of hydrolysis can be 0.90.