# Why copper sulphate is called blue vitriol?? Thank you.

Aug 8, 2018

Copper sulfate is a derivative of sulfuric acid, which was commonly called $\text{oil of vitriol...}$

#### Explanation:

And it could be produced from $\text{copper(II) oxide:}$

$C u O \left(s\right) + {H}_{2} S {O}_{4} \left(a q\right) \rightarrow C u S {O}_{4} \left(a q\right) + {H}_{2} O \left(l\right)$

The sulfate salt, as the hexahydrate, i.e. ${\left[C u {\left(O {H}_{2}\right)}_{6}\right]}^{2 +}$, is a beautiful blue colour, and macroscopic crystals can be grown..hence $\text{blue vitriol}$.

Note that anhydrous copper sulfate is WHITE...the colour derives from aquation of the cupric ion by water molecules...