Question

Sulphur and Magnesium are separately burnt in air. Name the products formed. When these products are dissolved in water and the solutions obtained are tested with litmus, what will be the result? Why?

Answer 1

Answer: Magnesium turns red litmus blue and sulphur turns blue litmus red.

Step-by-step explanation:

When a metal reacts with oxygen present in air, it forms basic oxide which simply means when they react with water, they form basic solution.

The chemical equation for the burning of magnesium (metal) in air and reaction with water of the product so formed are as follows:

`2Mg+O_2\rightarrow 2MgO`

`MgO+H_2O\rightarrow Mg(OH)_2\text{ (base)}`

When a non- metal reacts with oxygen present in air, it forms acidic oxide which simply means when they react with water, they form acidic solution.

The chemical equation for the burning of sulphur (non-metal) in air and reaction with water of the product so formed are as follows:

`S+O_2\rightarrow SO_2`

`SO_2+H_2O\rightarrow H_2SO_3\text{ (acid)}`

There are 2 types of litmus:

1. Red litmus: They turn the solution blue when dipped in basic solution.
2. Blue litmus: They turn the solution red when dipped in acidic solution.

Therefore, here, magnesium forms a basic solution, therefore it will turn red litmus blue whereas sulphur forms an acidic solution, so it will turn blue litmus red.