The brown ring test is used for the detection of :

1. CO₃^2-
2. Cl^-
3. NO₃^-
4. SO₃^2-

Sulphur reacts with conc. HNO₃ to give :

1. SO₂
2. H₂
3. H₂SO₄
4. H₂S

The acid which can be used to etch designs on brassware is :

1. HCl
2. HNO₃
3. H₂SO₄
4. H₂CO₃

HNO₃ is kept in reagent bottles because it is :

1. an oxidising agent
2. a reducing agent
3. hygroscopic in nature
4. decompose in the presence of light