Question

Which of the following substances is said to be isomorphous?
a.) White vitriol and blue vitriol
b.) Epsom salt and Glauber salt
c.) Blue vitriol and Glauber salt
d.) White vitriol and Epsom salt

Answer 1

Hint: We call two substances isomorphous when they have closely similar structure. They should contain the same chemical formulation and must contain atoms with similar chemical properties.

Complete step by step answer:
To answer this, firstly let us understand what does isomorphous actually mean!

Generally crystals are often referred to as isomorphous but remember only if they are closely similar in shape. As we can tell, isomorphous substances generally have similar chemical formulas, and even the cation radii are usually comparable.
Let us take an example to understand it better. For instance a group of minerals known as garnets, which generally vary in chemical composition but always have the same crystal structure. These crystals belong to the same space group.

Now let us discuss the compounds mentioned to us in the question.
Firstly, we have white vitriol. Zinc sulfate is the inorganic compound with the formula ${ ZnSO }_{ 4 }$ and it is generally called white vitriol. It is crystalline in nature and also exists in hydrated form as $ZnS{{O}_{4}}\cdot 7{{H}_{2}}O$.
Then we have blue vitriol. We commonly know cupric sulfate, ${ CuSO }_{ 4 }$ as blue vitriol which is a salt of copper. It has a bright blue color and is prepared by the treatment of copper oxides with sulfuric acid. It generally crystallizes as ${ CuSO }_{ 4 }\cdot 5{ H }_{ 2 }O$.
Then we have Epsom salt. It is the common name for magnesium sulfate. Its formula is $MgS{{O}_{4}}$. It also exists in hydrated form as $MgS{{O}_{4}}\cdot 7{{H}_{2}}O$.
And lastly we have Glauber salt. It is the common name for sodium sulphate its deca-hydrate salt is known as Glauber salt and its formula is $N{{a}_{2}}S{{O}_{4}}\cdot 10{{H}_{2}}O$.

Now, as we can see, all are sulphate salts but Epsom salt and white vitriol have the same water of crystallization and thus have similar structures.
Therefore, white vitriol and Epsom salt are said to be isomorphous.
So, the correct answer is “Option D”.

Note: You should know that blue vitriol is used as an insecticide, fungicide and in engraving. Whereas we white vitriol is used in the bleaching of paper, and in medicine as an astringent, styptic and emetic etc. Epsom salt is used as a pain reliever and reduces stress. Glauber salt is used as a laxative. It is often used for removal of overdose of drugs like paracetamol.