2.State one appropriate observation for each of following :

(i) Concentrated sulphuric acid is added drop wise to a crystal of hydrated copper sulphate.

(ii) Excess of chlorine gas is reacted with ammonia gas.

(iii) Copper sulphide is treated with dilute hydrochloric acid.

(iv) A few drops of dilute hydrochloric acid are added to silver nitrate solution,followed by addition of ammonium hydroxide solution.

(v) Electricity is passed through molten lead bromide.

1. When concentrated sulfuric acid is added to hydrated copper sulfate, copper sulfate loses its water of crystallization and the color changes from blue to white.

2. When excess of chlorine reacts with ammonia the reaction can be explosive due to the formation of highly explosive nitrogen trichloride.

3. Copper sulfide under normal conditions does not react with hydrochloric acid.

4. When hydrochloric acid reacts with silver nitrate a white precipitate of silver chloride is formed which then dissolves when ammonium hydroxide is added due to the formation of a silver ammonia complex.

5. When electricity is passed through molten lead bromide, the lead bromide is broken down to form lead and bromine.

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