Equilibrium — Chemistry STD 11 Science — Question

1. Dissociation Constant of an Acid K_a: It measures the ability of an acid to lose [H⁺] experimentally.

$\text{CH}_3\text{COOH}(\text{l})+\text{H}_2\text{O}(\text{l})\\\rightleftharpoons\text{CH}_3\text{COO}^-(\text{aq})+\text{H}_3\text{O}^+(\text{aq})$

$\text{K}_{\text{a}}=\frac{[\text{CH}_3\text{COO}^-][\text{H}_3\text{O}^+]}{[\text{CH}_3\text{COOH}]}$

2. Buffer Solution: The solution whose pH does not change by adding small amount of H+ or OH⁺ is called buffer solution. e.g. mixture of CH₃COOH and CH₃COONa is a buffer solution.

3. Solubility Product: It is a product of molar concentration of ions formed in a saturated solution at a given temperature raised to the power equal to the number of each ions formed by 1 mole of sparingly soluble compound.

$\text{e.g. AgCl}(\text{s})\rightleftharpoons\text{Ag}^+(\text{aq})+\text{Cl}^-\text{(aq)};$

$\text{K}_{\text{sq}}=[\text{Ag}^+][\text{Cl}^-]$