Question

The percentage of water of crystallisation of a sample of blue vitriol is:

• A. $34.07$%
• B. $35.07$%
• C. $36.07$%
• D. $37.07$%

Answer 1

The correct option is C $36.07$%

Blue vitriol is copper sulphate penta hydrate $CuS{O}_4\cdot 5H_{2}O$

The molecular weight of $CuS{O}_4\cdot 5H_{2}O$ is:
$63.5+32+4\left(16\right)+5\left(18\right)=249.5$ g/mol

The percentage of water of crystallisation of a sample of blue vitriol is,

$\to \frac{5\times 18}{249.5}\times 100=$ $36.07$%.

Hence, option $C$ is correct.