sblock Elements 1 Question 6
2. The incorrect statement is
(2019 Main, 12 April II)
(a) lithium is the strongest reducing agent among the alkali metals.
(b) lithium is least reactive with water among the alkali metals.
(c) $\mathrm{LiNO}{3}$ decomposes on heating to give $\mathrm{LiNO}{2}$ and $\mathrm{O}_{2}$.
(d) $\mathrm{LiCl}$ crystallise from aqueous solution as $\mathrm{LiCl} \cdot 2 \mathrm{H}_{2} \mathrm{O}$.
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Solution:
- Statement (c) is incorrect. $\mathrm{LiNO}{3}$ (Lithium nitrate) on heating gives a mixture of $\mathrm{Li}{2} \mathrm{O}, \mathrm{NO}{2}$ and $\mathrm{O}{2}$.
$$ 4 \mathrm{LiNO}{3} \stackrel{\Delta}{\longrightarrow} 2 \mathrm{Li}{2} \mathrm{O}+4 \mathrm{NO}{2} \uparrow+\mathrm{O}{2} \uparrow $$
Among the alkali metals, lithium is the strongest reducing agent.
