Q15 / 160 · AP EAMCET 2023 (17 May Shift 1) · Chemistry
Which of the following statement(s) is/are correct?
(i) $\mathrm{Li} \mathrm{NO} \mathrm{NO}_3, \mathrm{Ba}\left(\mathrm{NO}_3\right)_2$ both will give $\mathrm{NO}_2$ on heatiing
(ii) $\mathrm{BaSO}_4$ is less soluble in water than $\mathrm{CaSO}_4$
(iii) Alkaline earth metals do not dissolve in liquid ammonia
- Ai only
- Correct answerBi, ii only
- Ci, ii \& iii
- Di, iii only
Solution
$4 \mathrm{Li} \mathrm{NO}_3 \stackrel{\Delta}{\longrightarrow} 2 \mathrm{Li}_2 \mathrm{O}+4 \mathrm{NO}_2+\mathrm{O}_2$ (anomalous behaviour)
$2 \mathrm{Ba}\left(\mathrm{NO}_3\right)_2 \stackrel{\Delta}{\longrightarrow} 2 \mathrm{BaO}+4 \mathrm{NO}_2+\mathrm{O}_2$
Thus, (i) is correct.
The solubility of alkaline earth metals decreases down the group due to a decrease in hydration enthalpy compared to the lattice enthalpy.
Thus, $\mathrm{BaSO}_4$ will be less soluble in water than $\mathrm{CaSO}_4$. Thus, (ii) is also correct.
Alkaline earth metals dissolve in liquid ammonia to form a coloured solution.
$\mathrm{M}+(\mathrm{x}+\mathrm{y}) \mathrm{NH}_3 \rightarrow\left[\mathrm{M}\left(\mathrm{NH}_3\right)_{\mathrm{x}}\right]^{2+}+2\left[\mathrm{e}\left(\mathrm{NH}_3\right)_{\mathrm{y}}\right]^{-}$
Thus, (iii) is incorrect.
Hence, the correct answer is option: 'B'.