JEE Main 2025 · Chemistry · s-Block, p-Block Elements and Hydrogen · easy

One mole of LiNO3 and one mole of NaNO3 are heated strongly in two separate vessels until decomposition is complete. The ratio of moles of O2 evolved…

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One mole of

\mathrm{LiNO_3}

and one mole of

\mathrm{NaNO_3}

are heated strongly in two separate vessels until decomposition is complete. The ratio of moles of

\mathrm{O_2}

evolved from

\mathrm{LiNO_3}

to that from

\mathrm{NaNO_3}

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Answer: (D) $1:2$

Lithium nitrate decomposes like the nitrates of heavy metals:

\mathrm{4LiNO_3\to2Li_2O+4NO_2+O_2}

, so

1

mol gives

0.25

mol

\mathrm{O_2}

. Sodium nitrate gives the nitrite:

\mathrm{2NaNO_3\to2NaNO_2+O_2}

, so

1

mol gives

0.5

mol

\mathrm{O_2}

. Ratio

=0.25:0.5=1:2

. The small

\mathrm{Li^+}

has high polarising power and stabilises

\mathrm{O^{2-}}

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