Name two metals which react violently with cold water. Write any three observations you would make when such a metal is dropped into water. How would you identify the gas evolved, if any, during the reaction?

Solution:

The two metals that react aggressively with cold water are sodium and potassium.

Three points to consider:

1. The reaction is exothermic, which means it produces a lot of heat.

2.Hydrogen is produced.

3. There is a small explosion with a pop sound.

If the gas evolved is hydrogen gas, a pop sound will be heard.