Question

In brown ring test, a freshly prepared ferrous sulphate solution is used because:

• A. Ferrous sulphate when exposed to atmosphere oxidizes to ferric sulphate.
• B. Ferrous sulphate when exposed to atmosphere reduces to ferric sulphate.
• C. Ferric sulphate doesn't give a brown ring.
• D. Ferric sulphate will also give a brown ring but will not stay for a longer times.

Answer 1

Answer: (A), (C)

The correct options are
A

Ferrous sulphate when exposed to atmosphere oxidizes to ferric sulphate.

C

Ferric sulphate doesn't give a brown ring.

In brown ring test, a freshly prepared ferrous sulphate solution is used because on exposure to the atmosphere , it oxidizes to ferric sulphate which will not give brown ring.

$12FeS{O}_4+3O_2->4F{e}_2{\left(S{O}_4\right)}_3+2F{e}_2{O}_3$