A student observed that the temperature of water

increased when a salt was dissolved in it. The

student should conclude that dissolving the salt

caused

A.

formation of an acidic solution

B.

formation of a basic solution

C.

an exothermic reaction

D. an endothermic reaction

Increasing temperature increases the solubility of most salts, but not all. The reason for the differences is that dissolution involves three steps: breaking bonds of salt in the lattice; forming cavities in water the same size as the ions; interacting the salt with water in the cavity.

answer: -

reaction:

na + cl ⇌ nacl

balanced chemical equation:

na + 2cl ⇌ nacl2

sodium + clorine goes to form sodium chloride (table salt).

the product is nacl2.

and the reactants are na and cl.

(note: if you don’t know what ⇌ means, read below: -

⇌(double head arrow) means reversible reaction).