Concept:The thermal decomposition products of metal nitrates depend on the reactivity of the metal. Alkali metal nitrates (except Lithium) decompose differently than heavy metal nitrates.
Formula:$$ 2\text{NaNO}_{3(s)} \xrightarrow{\Delta} 2\text{NaNO}_{2(s)} + \text{O}_{2(g)} $$
Solution:- When heavy metal nitrates (like Lead or Copper) are heated, they decompose completely into the metal oxide, nitrogen dioxide gas, and oxygen gas.
- However, Sodium is a highly reactive Group 1 alkali metal.
- When Sodium nitrate (\( \text{NaNO}_3 \)) is heated, it undergoes a partial decomposition. It melts and releases oxygen gas, leaving behind a stable salt, Sodium nitrite (\( \text{NaNO}_2 \)).
- Therefore, the products are strictly \( \text{NaNO}_2 \) and \( \text{O}_2 \).
Why other options are incorrect:- Option A describes the decomposition pattern of a less reactive metal (like Copper). Options C and D list chemically unrealistic or unstable decomposition products for this reaction.
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