NEET UG CHEMISTRY MCQ: THERMODYNAMICS

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Application +4 | -1

{C_2}{H_6}\left( g \right) + \frac{7}{2}{O_2}\left( g \right) \to 2C{O_2}\left( g \right) + 3{H_2}O\left( l \right);\,\Delta H = - 1560\,KJ

{C_2}{H_2}\left( g \right) + \frac{5}{2}{O_2}\left( g \right) \to 2C{O_2}\left( g \right) + {H_2}O\left( l \right);\,\Delta H = - 1310\,KJ

{H_2}\left( g \right) + \frac{1}{2}{O_2}\left( g \right) \to {H_2}O\left( l \right);\Delta H = - 290\,KJ

Enthalpy of hydrogenation of ethyne

\left( {{C_2}{H_2}} \right)

View answer and explanation

Correct option: C

- 330 KJ

Option C (– 330 KJ) is correct because it is the enthalpy change for the hydrogenation of ethyne to ethane, calculated using Hess's law from the given combustion enthalpies.

More Questions from THERMODYNAMICS

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The internal energy of one mole of a gas is: An ideal gas is allowed to expand both reversibly and irreversibly in an isolated system. If

{T_i}

is the initial temperature and

{T_f}

is the final temperature, which of the following statements is correct? For which of the process, ∆S is negative? The work done by a weightless piston in causing an expansion ∆V (at constant temperature), when the opposing pressure, P is variable, is given by: Assertion :- At constant pressure of the change

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

work done is negative.

Reason :- During phase transition work done is always negative. For the reaction,

\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}

. Hence,

\Delta G