MCQ
- A
- B
- C
- DAll of these.
Explanation:

Options (a), (b) and (c) are same molecule, i.e. nitrobenzene.
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$\frac{1}{2}{P_4}(s) + 3C{l_2}(g) \to 2PC{l_3}(l)\,;$ $\Delta H=-635 \,kJ$
$PC{l_3}(l) + C{l_2}(g) \to PC{l_5}(s)\,;$ $\Delta H=-137\, kJ$
The value of heat of formation of $PCl_5$ is ......$kJ\,mol^{-1}$
For the reaction $3 CaO +2 Al \rightarrow 3 Ca + Al _{2} O _{3}$ the standard reaction enthalpy $\Delta_{ r } H ^{0=}$ .......... $kJ$.
(Round off to the Nearest Integer).
Compound $(B)$ in above reaction is