Question

Write balanced chemical equation for developing a black and white photographic film. Also give reason why the solution of sodium thiosulphate on acidification turns milky white and give balance equation of this reaction.

Answer 1

The following reactions are used in developing the photographic film

AgBr react with sodium thiosulphate (hypo) to give soluble sodium argent othiosulphate.

(b) Aqueous solution of sodium thiosulphate (Na₂S₂O₃) on acidification gives milky white turbidity of colloidal sulphur