Lithium nitrate and sodium nitrate, when heated separately, respectively, give

We need to determine the thermal decomposition products of lithium nitrate and sodium nitrate when heated separately.

Lithium, being the smallest alkali metal, has a very high charge density. Due to its strong polarising power, lithium nitrate decomposes differently from the nitrates of other alkali metals. When heated, $$LiNO_3$$ decomposes completely into the oxide:

$$4LiNO_3 \xrightarrow{\Delta} 2Li_2O + 4NO_2 + O_2$$

This happens because the small $$Li^+$$ ion strongly polarises the large nitrate ion, destabilising it and causing it to break down entirely into the oxide rather than just the nitrite.

Now, sodium nitrate behaves like a typical alkali metal nitrate (Na, K, Rb, Cs). These metals have lower polarising power, so their nitrates decompose only partially — losing one oxygen to form the nitrite:

$$2NaNO_3 \xrightarrow{\Delta} 2NaNO_2 + O_2$$

Hence, lithium nitrate gives $$Li_2O$$ and sodium nitrate gives $$NaNO_2$$ upon heating.

Hence, the correct answer is Option C: $$Li_2O$$ and $$NaNO_2$$.