Question

Identify \(A\) and \(B\) from the following reaction
\[ NaNO_3 \xrightarrow{\Delta} xA + yB \]

• A. \(NaNO_2,\; O_2\)
• B. \(Na_2O,\; NO_2\)
• C. \(Na_2O,\; NO\)
• D. \(Na,\; NO_2\)

Hint:

Thermal decomposition of alkali metal nitrates: \[ MNO_3 \xrightarrow{\Delta} MNO_2 + O_2 \] except lithium nitrate, which forms oxide instead of nitrite.

Answer 1

The Correct Option is A

Step 1: Recall how nitrates decompose.
Alkali metal nitrates, except lithium nitrate, decompose on heating to give the corresponding nitrite and oxygen gas.
Step 2: Apply this to sodium nitrate.
Sodium is a typical alkali metal, so $NaNO_3$ follows this pattern rather than breaking down to the oxide.
Step 3: Write the balanced reaction.
$2NaNO_3 \xrightarrow{\Delta} 2NaNO_2 + O_2$.
Step 4: Identify the products.
Comparing with $NaNO_3 \rightarrow xA + yB$, we get $A = NaNO_2$ and $B = O_2$.
Step 5: Reject the wrong options.
$Na_2O$ with $NO_2$ or $NO$, and $Na$ with $NO_2$, would require breaking down to the oxide or metal, which alkali nitrates do not do on simple heating.
Step 6: State the answer.
The products are $NaNO_2$ and $O_2$, which is option (1). \[ \boxed{NaNO_2,\ O_2} \]