Question

Assertion :Magnesium metal burns in air to give a white ash.When this ash is treated with water, the odour of ammonia can be detected. Reason: Mg burns in air to form MgO and $M{g}_3{N}_2$. It is the $M{g}_3{N}_2$ which on hydrolysis gives $N{H}_3$.
$2Mg+O_2\to 2MgO$
$3Mg+N_2\to M{g}_3{N}_2$
$M{g}_3{N}_2+6H_{2}O\to 3Mg(OH{)}_2+2N{H}_3\uparrow$

• A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
• B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
• C. Assertion is correct but Reason is incorrect
• D. Both Assertion and Reason are incorrect

Answer 1

The correct option is A Both Assertion and Reason are correct and Reason is the correct explanation for Assertion

Magnesium metal burns in air to give a white ash.When this ash is treated with water, the odour of ammonia can be detected.
Mg burns in air to form MgO and $M{g}_3{N}_2$. It is the $M{g}_3{N}_2$ which on hydrolysis gives $N{H}_3$.

$2Mg+O_2\to 2MgO$

$3Mg+N_2\to M{g}_3{N}_2$

$M{g}_3{N}_2+6H_{2}O\to 3Mg(OH{)}_2+2N{H}_3\uparrow$
So Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
Hence option A is correct.