when a reactive metal is added to water, bubbles or fizzing can be observed. Explain the appearance of the bubbles​

This is because of the release of hydrogen gas in the reaction.

Explanation:

Metals react with water and produce a metal oxide and hydrogen gas. It also starts floating due to the bubbles of hydrogen gas sticking to its surface.

For eg:

2Mg. + 2H2O > 2MgOH + H2

Here,

Metal taken is magnesium(2Mg) which when reacts with water(2H2O) to form its oxide form (2MgOH) and hydrogen gas(H2) is released which comes outside water as bubbles.