• 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?

Sodium and potassium are the two metals which reacts violently with cold water. Three observations:

1. Reaction is exothermic and huge amount of heat is
2. Hydrogen gas is evolved
3. Small explosion with a pop sound takes place

If the gas evolved is hydrogen gas then it will make a pop sound