Heat of combustion ∆H for C(s), ${{\rm{H}}_2}$(g) and ${\rm{C}}{{\rm{H}}_4}$ (g) are -94,-68 and -213 kcal/mole then ∆H for ${\rm{C}}\left( s \right) + 2{{\rm{H}}_2}\left( {\rm{g}} \right) \to {\rm{C}}{{\rm{H}}_4}\left( {\rm{g}} \right){\rm{i}}s:$

NEET UG CHEMISTRY MCQ: THERMODYNAMICS

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Application +4 | -1

Heat of combustion ∆H for C(s),

{\mathrm{H}_2}

(g) and

\mathrm{C}{\mathrm{H}_4}

(g) are -94,-68 and -213 kcal/mole then ∆H for

\mathrm{C}\left( s \right) + 2{\mathrm{H}_2}\left( \mathrm{g} \right) \to \mathrm{C}{\mathrm{H}_4}\left( \mathrm{g} \right)\mathrm{i}s:

View answer and explanation

Correct option: A

-17 kcal

Option A (-17 kcal) is correct because it is calculated using Hess's law by manipulating the given heats of combustion.

Practice All Chapter MCQs →

{T_i}

{T_f}

\mathrm{H}_2 \mathrm{O}(\mathrm{s}) \rightarrow \mathrm{H}_2 \mathrm{O}(\mathrm{g})

\mathrm{X}_2 \mathrm{O_4(l}) \longrightarrow 2 \mathrm{XO}_2(\mathrm{g}), \Delta U=2.1 \mathrm{~kcal}, \Delta S=20 \mathrm{~cal} \mathrm{~K}^{-1}

300 \mathrm{~K}

\Delta G