Question

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?

Answer 1

Sodium and potassium are two metals that react violently with cold water.

Observations made when such a metal is dropped in water:
(i) The reaction is highly exothermic, i.e. a huge amount of heat is produced.
(ii) Hydrogen gas is evolved in the reaction
(iii) Little explosions take place because the heat produced in the chemical reaction burns the hydrogen gas.

Hydrogen gas can be identified by the pop sound produced during the reaction of metal with cold water.