Write balanced equation for the reaction :

Copper oxide and dilute hydrochloric acid.

Write balanced equation for the following reaction:

Manganese $\left(\mathrm{IV}\right)$ oxide and concentrated hydrochloric acid.

Give the balanced equation:

When ethylene is burnt in an excess of oxygen.

Given balanced equation:

Ethylene reacts with chlorine.

Give balanced equation:

Ethylene combines with hydrogen chloride.

Give balanced equation:

A mixture of ethylene and hydrogen is passed over nickel at $150° \mathrm{C}$.