Question

Give chemical reaction of copper sulphate with water.

Answer 1

Hint: Copper sulphate is an inorganic compound with chemical formula $CuS{O_4}.{\rm X}$, where X is molecules of water of crystallization and can range from 0 to 5. The pentahydrate is the most common form. It’s formula is $CuS{O_4}.5{H_2}O$.

Complete answer:
> Copper sulphate pentahydrate is known as blue vitriol. its formula is $CuS{O_4}.5{H_2}O.$
Pentahydrate is water of crystallization.
> The substances that contain water of crystallization are called hydrated substances.
> The reaction between ${H_2}O$ and $CuS{O_4}$ gives $CuS{O_4}.5{H_2}O$.
$CuS{O_4} + 5{H_2}O \to CuS{O_4}.5{H_2}O$
Hydrated $CuS{O_4}$ is blue in color.
It gives copper sulphate monohydrate which is bluish white in color.
> $CuS{O_4}.5{H_2}O\xrightarrow{\Delta }CuS{O_4} - {H_2}O + 4{H_2}O$
When compounds dissolve in water, it dissociates to form ions.
> $CuS{O_4} + {H_2}O \to C{u^{2 + }} + SO_4^{2 - }$

The white solid turns blue in presence of water.

Note: The compound with water molecules is called water of crystallization. There are five molecules of water of crystallization in copper sulphate. When pure copper sulphate is kept in water it starts dissolving and heat is released. The colour changes to blue due to the presence of 5 molecules of water.