Question

A white solid when dropped in water produces a hissing sound.what maybe the solid ? Give the chemical reaction for the above.

Answer 1

According to the circumstances mentioned in the question the solid substance is probably the calcium oxide or CaO. The calcium oxide or CaO reacts with the water and produces calcium hydroxide or Ca(OH)2. This an exothermic reaction. And due to the creation of heat,the whole reaction produces the hissing sound

reaction:

CaO + $H_{2}$O ---->   Ca$(OH)_{2}$