Question

Why do CA and Mg metal floating on water surface ?

Answer 1

Calcium (Ca) reacts with cold water to form Calcium hydroxide and hydrogen gas.

Heat produced is less that it is not enough to burn hydrogen gas.

The Calcium metal floats on water because the bubbles of Hydrogen gas formed during reaction stick to its surface.

Magnesium (Mg) metal reacts with hot water to form magnesium hydroxide and hydrogen gas.

The magnesium metal floats on water because the bubbles of Hydrogen gas formed during reaction stick to its surface.

Hope it helps! :)