(i) Which concentrated acid will oxidize sulphur directly to sulphuric acid ? Write the equation for the same.

(ii) Complete the following : concentrated sulphuric acid is used in the laboratory preparation of nitric acid and hydrochloric acid because it is — (less volatile/stronger) in comparison to these two acids.

(iii) Write the observation and the balanced equation, when a paper dipped in acidified potassium dichromate solution is put on the mouth of a test tube containing sulphur dioxide gas.

Give equations for the following :

(i) Preparation of acetylene

(ii) Preparation of ethyl alcohol

(iii) Addition of chlorine to ethylene

(iv) Preparation of ethane

(v) Sulphurous acid reacts with bromine.

1 gram mixture of NaCl and NaNO₃ is dissolved in water and treated with an excess of AgNO₃ solution. 1.43 g of precipitate is formed. Calculate percentage of sodium chloride in the mixture. [5]

[Ag = 108, Na = 23, N = 14, O = 16, Cl = 35.5].

[Dilute sulphuric acid, copper, iron, sodium, zinc, copper carbonate and sodium carbonate]

Choosing only from the list of substances mentioned above, write an equation for the reaction which you would use in the lab to obtain :

(i) Zinc carbonate

(ii) Copper sulphate

(iii) Sodium sulphate

(iv) Iron sulphate