Question

Which of the following compound on heating gives N₂O ?

• A. Pb(NO₃)₂
• B. NH₄NO₃
• C. NH₄NO₂
• D. NaNO₃

Answer 1

The Correct Option is B

When ammonium nitrate \((NH_4NO_3)\) is heated, it decomposes to form nitrous oxide \((N_2O)\), water, and nitrogen dioxide:

\(2 NH_4NO_3 → 2 N_2O + 4 H_2O + O_2\)

This reaction is a classic example of the decomposition of ammonium nitrate on heating, producing \(N_2O\) (nitrous oxide), which is also known as laughing gas.

The correct answer is (B) : \(NH_4NO_3\).

Answer 2

1. Consider the decomposition reactions of the given compounds

- Pb(NO₃)₂ (Lead(II) nitrate): Upon heating, lead(II) nitrate decomposes to give lead(II) oxide (PbO), nitrogen dioxide (NO₂), and oxygen (O₂).
$$ 2Pb(NO_3)_2(s) \rightarrow 2PbO(s) + 4NO_2(g) + O_2(g) $$

- NH₄NO₃ (Ammonium nitrate): Upon heating, ammonium nitrate decomposes to give dinitrogen monoxide (N₂O) and water (H₂O).
$$ NH_4NO_3(s) \rightarrow N_2O(g) + 2H_2O(g) $$

- NH₄NO₂ (Ammonium nitrite): Upon heating, ammonium nitrite decomposes to give nitrogen gas (N₂) and water (H₂O).
$$ NH_4NO_2(s) \rightarrow N_2(g) + 2H_2O(g) $$

- NaNO₃ (Sodium nitrate): Upon heating, sodium nitrate decomposes to give sodium nitrite (NaNO₂) and oxygen (O₂).
$$ 2NaNO_3(s) \rightarrow 2NaNO_2(s) + O_2(g) $$

2. Identify the compound that produces N₂O upon heating
From the above decomposition reactions, we can see that ammonium nitrate ($NH_4NO_3$) produces dinitrogen monoxide ($N_2O$) upon heating.

Final Answer:
(B) $NH_4NO_3$