Question

How will you disntinguish between ferrous sulphate solution and ferric sulphate solution using sodium hydroxide solution?

Answer 1

$\bold{FERROUS}$

Iron or ferrous is a metal with valency +2 which oxidises or shows variable valency and exhibits valency +3 and becomes ferric.

◼Variable valency is the one in which the one electron penultimate shell jumps out to the outermost shell thereby increasing the valency electron.

$\bold{FERROUS \: SULPHATE AND }FERRIC \: SULPHATE }$

ADD SODIUM HYDROXIDE TO THE AQUEOUS SOLUTION OF BOTH THE SALS.

◼For ferrous sulphate

When sodium hydroxide is added to aqueous solution of ferrous sulphate it gives out a dirty green precipitate.

EQUATION :-

$2 NaOH + FeSO_4 \longrightarrow Na_2SO_4 + Fe(OH)_2$

◼For ferrous sulphate

When sodium hydroxide is added to aqueous solution of ferric sulphate it gives out a reddish brown precipitate.

EQUATION :-

$Fe_2(SO_4)_3 + 2NaOH \longrightarrow 2Fe(OH)SO_4 + Na_2SO_4$