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NEET UG CHEMISTRY MCQ: THERMODYNAMICS

1 Medium

1 of 1

Analyzing +4 | -1

For which reaction(s) is the

\Delta \mathrm{H}

value equal to the

\Delta \mathrm{E}

value?
(I)

\mathrm{CH}_4(\mathrm{g})+2 \mathrm{O}_2(\mathrm{g}) \rightarrow \mathrm{CO}(\mathrm{g})+2 \mathrm{H}_2 \mathrm{O} (l)

(II)

\mathrm{C}_2 \mathrm{H}_4(\mathrm{g})+3 \mathrm{O}_2(\mathrm{g}) \rightarrow 2 \mathrm{CO}(\mathrm{g})+2 \mathrm{H}_2 \mathrm{O}(\mathrm{g})

View answer and explanation

Correct option: B

II only

Option B is correct.

\Delta H = \Delta E + \Delta n_g RT

.

\Delta H = \Delta E

when

\Delta n_g = 0

. In reaction II,

\Delta n_g = (2+2) - (1+3) = 0

. In reaction I,

\Delta n_g = 1 - (1+2) = -2

.

More Questions from THERMODYNAMICS

Practice All Chapter MCQs →

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}

\Delta G