Question

A WHITE SOLID WHEN DROPPED IN WATER PRODUCES A HISSING SOUND. WHAT THE SOLID MAY BE? GIVE THE CHEMICAL REACTION FOR THE ABOVE. NAME THE PRODUCT FORMED.

Answer 1

this solid may be calcium oxide
cao +h2o = CA (oh) 2
the product so formed is calcium hydroxide

Answer 2

According to the circumstances mentioned in the question should be sodium.

Because,sodium is extremely reactive with the water and it is a white coloured solid material.

The chemical reaction of the occured reaction will be:

Na+H20 => NaOH + H2.

And this is an extremely exothermic reaction which creates a lot of heat ,that's why sodium is always contained in dry places.