1. The most reactive metal is
a)Iron b)Gold c) Potassium d) Zinc
2. What happens when aluminium metal is placed in the freshly prepared solution of sodium hydroxide ? What does a "POP" sound indicates , when a burning matchstick is brought near the mouth of the test tube?
(a). Out of the given metals potassium is the most reactive metal as it reacts violently with water, it can react with moisture present in air. Gold is an inert metal and iron reacts with hot water or steam only. And, the reaction of Zinc is not violent like potassium.
(b). The reaction is given as under:
Al + 3NaOH --------> Al (OH)3 + 3Na
Pop sound indicates that hydrogen gas is evolved in the reaction.