Question

Match the formula for the following compound: 

Answer 1

Answer: $MgSO_4.7H_2O$

Explanation:

$MgSO_4$ is an ionic compound because aluminium element is a metal and hydrogen element is a non-metal. The bond formed between a metal and a non-metal is always ionic in nature.

The nomenclature of ionic compounds is given by:

1. Positive is written first.

2. The negative ion is written next and a suffix is added at the end of the negative ion. The suffix written in case of $SO_4^{2-}$ is '-ate'.

Hence, the name of $MgSO_4$ is magnesium sulphate.

The water of crystallization is written as hydrate with the number of water molecules. As the name is heptahydrate, that means 7 water molecules are present.

Therefore, the correct answer is $MgSO_4.7H_2O$

Answer 2

valence of magnesium is 2

and valence of sulfate-ion is 2 too

answer: MgSO4•7H2O