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.

it is the most commonly accepted one

there are two significant figures.