The oxidation state of chlorine in potassium chlorate is?

A gaseous metallic chloride MClx consists of 20.22% of M by mass. The formula of the chloride is?
[M = 27, Cl = 35.5]

In which of the following reactions can the oxidation number of the nitrogen be said to have increased?

A hydrocarbon X with a molar mass of 26 consists of 92.3% carbon. What is its molecular formular?

The percentage of water of crystallization in ZnSO\(_4\).7H\(_2\)O is?
[Zn = 65, S = 32, O = 16, H = 1]