n m+n Example . • Establish a relationship between the solubility product and molar solubility for the following a) BaSO b) Ag (CrO ) BaSO (s) Ba (aq)+SO (aq) K =[Ba ][SO ] H O + sp + = (s) (s) K S sp Ag CrO (s) 2Ag (aq)+CrO (aq) H O ← K =[Ag ] [CrO ] = (2s) (s) K =4s sp + sp XII U8-Ionic XII U8-Ionic - - - - Summary According to Arrhenius, an acid is a substance that dissociates to give hydrogen ions in water. According to Lowry and Bronsted concept, an acid is defined as a substance that has a tendency to donate a proton to another substance and base is a substance that has a tendency to accept a proton from other substance. According to Gilbert .
N. Lewis , an acid is a species that accepts an electron pair while base is a species that donates an electron pair. ionic product (ionic product constant) of water (K w )=[H O + ][OH – ] pH of a solution is defined as the negative logarithm of base of the molar concentration of the hydronium ions present in the solution. pH = –log [H O + ] when dilution increases, the degree of dissociation of weak electrolyte also increases.
This statement is known as Ostwald’s dilution Law. When a salt of a weak acid is added to the acid itself, the dissociation of the weak acid is suppressed further this is known as common ion effect Buffer is a solution which consists of a mixture of a weak acid and its conjugate base (or) a weak base and its conjugate acid. Buffer capacity and buffer index is defined as the number of gram equivalents of acid or base added to litre of the buffer solution to change its pH by unity. β = dB d(pH) Henderson – Hasselbalch equation For Acid buffer ⇒ pH = pK log [salt] [acid] a For Basic buffer ⇒ pOH = pK log [salt] [base] b Hydrolysis