In a complexometric titration of metal ion with ligand
M(Metal ion) + L(Ligand) $$ \to $$ C(Complex) end point is estimated spectrophoto - metrically (through light absorption). If 'M' and 'C' do not absorb light and only 'L' absorbs, then the titration plot between absorbed light (A) versus volume of ligand 'L' (V) would look like :

Products A and B formed in the following reactions are respectively :

The major product of the following reaction is :

Assuming ideal gas behaviour, the ratio of density of ammonia to that of hydrogen chloride at same temperature and pressure is : (Atomic wt. of Cl = 35.5 u)