Give reasons for the following:

The yellow colour of nitric acid obtained in the laboratory is removed by bubbling air through it.

Give reasons for the following:

Nitric acid affects the skin if it accidently falls on it, staining the skin yellow.

Give balanced equations for the following conversions A to E.

1. $\text{Copper} \xrightarrow{\text{A}} \text{Copper nitrate} \xrightarrow{\text{B}} \text{Copper oxide} \xrightarrow{\text{C}} \text{Copper}$

2. $\text{Sulphur} \xrightarrow{\text{D}} \text{Sulphuric acid} \xleftarrow{\text{E}} \text{Sulphur dioxide}$

Name the oxidised product when the following 1 to 5 react with nitric acid

1. Sulphur [with conc. acid]
2. Zinc [with dil. acid]
3. Aqueous soln. of SO₂ [with dil. acid]
4. Acidified iron [II] sulphate [with dil. acid]
5. Carbon [with conc. acid]