Question

A strip of magnesium is burnt in air and the product obtained is allowed to react with sulphuric acid. Which of the following ions are present in the final salt obtained?

• A. ${\text{Mg}}^{+}$ and ${\text{SO}}_4^{2-}$
• B. ${\text{Mg}}^{2+}$ and ${\text{SO}}_4^{2-}$
• C. ${\text{H}}^{+}$ and ${\text{SO}}_3^{2-}$
• D. ${\text{Mg}}^{2+}$ and ${\text{SO}}_3^{2-}$

Answer 1

The correct option is B ${\text{Mg}}^{2+}$ and ${\text{SO}}_4^{2-}$

When magnesium strip is burned in air, magnesium oxide is obtained.

$2\text{Mg}+{\text{O}}_2\to 2\text{MgO}$

Being a metallic oxide, it is basic in nature, and with sulphuric acid it undergoes neutralization reaction. As a result, magnesium sulphate salt and water are formed as products.

$\text{MgO}+{\text{H}}_2{\text{SO}}_4\to {\text{MgSO}}_4+{\text{H}}_2\text{O}$

Magnesium sulphate, ${\text{MgSO}}_4$, has ${\text{Mg}}^{2+}$ and ${\text{SO}}_4^{2-}$ as cation and anion respectively.