Question

What happens when calcium and potassium are put in water?

Answer 1

a) Calcium in water

When a metal reacts with water( cold water or hot water) then the products formed are metal hydroxide and hydrogen gas.

Calcium reacts with cold water to form calcium hydroxide and hydrogen gas:

$Ca+2H_{2}O\to Ca(OH{)}_2+H_2$

b) potassium in water

Potassium reacts violently with cold water to form potassium hydroxide and hydrogen gas:

$2K+2H_{2}O\to 2KOH+H_2+heat$

In this reaction so much heat is produced get hydrogen gas formed catches fire and burns explosively.