Question

what happens when potassium and sodium reacts with water ?

Answer 1

1) When potassium reacts with water it burns with a flame of lilac colour.Similarly sodium reacts with water very fast to form it's respective hydroxide. They both being highly reactive metal,the reaction is exothermic in nature.

$$\begin{gathered} 2Na+2H_{2}O\to 2NaOH+H_2 \\ 2K+2H_{2}O\to 2KOH+H_2 \end{gathered}$$