Question

Which of the following is incorrect?

• A. $L{i}_{2}C{O}_3\left(s\right)\stackrel{\Delta }{\to }L{i}_{2}O\left(s\right)+C{O}_2\left(g\right)$
• B. $2LiN{O}_3\left(s\right)\stackrel{\Delta }{\to }2LiN{O}_2\left(s\right)+O_2\left(g\right)$
• C. $6Li\left(s\right)+N_2\left(g\right)\stackrel{\Delta }{\to }2L{i}_{3}N\left(s\right)$
• D. $2Li\left(OH\right)\left(s\right)\stackrel{\Delta }{\to }L{i}_{2}O\left(s\right)+H_{2}O\left(l\right)$

Answer 1

The correct option is B $2LiN{O}_3\left(s\right)\stackrel{\Delta }{\to }2LiN{O}_2\left(s\right)+O_2\left(g\right)$

Lithium has a diagonal relationship with magnesium.
(a) Carbonates of Li and Mg decompose on heating and liberate $C{O}_2$
$L{i}_{2}C{O}_3\left(s\right)\stackrel{\Delta }{\to }L{i}_{2}O\left(s\right)+C{O}_2\left(g\right)$
$MgC{O}_3\left(s\right)\stackrel{\Delta }{\to }MgO\left(s\right)+C{O}_2\left(g\right)$

(b)&(d) Nitrates and hydroxides of both Li and Mg decompose on heating and produce oxides. Option (b) is incorrect.
$4LiN{O}_3\left(s\right)\stackrel{\Delta }{\to }2L{i}_{2}O\left(s\right)+4N{O}_2\left(g\right)+O_2$
$2Mg\left(N{O}_3{)}_2\right(s\left)\stackrel{\Delta }{\to }2MgO\right(s)+4N{O}_2(g)+O_2(g)$

$2Li\left(OH\right)\left(s\right)\stackrel{\Delta }{\to }L{i}_{2}O\left(s\right)+H_{2}O\left(l\right)$
$Mg\left(OH{)}_2\right(s\left)\stackrel{\Delta }{\to }MgO\right(s)+H_{2}O(l)$

(c) Li and Mg both combine directly with $N_2$ to give nitrides.
$6Li\left(s\right)+N_2\left(g\right)\stackrel{\Delta }{\to }2L{i}_{3}N\left(s\right)$
$3Mg\left(s\right)+N_2\left(g\right)\stackrel{\Delta }{\to }M{g}_3{N}_2\left(s\right)$