NEET UG CHEMISTRY MCQ: THERMODYNAMICS

1 Easy

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Analyzing +4 | -1

Given below are two statements one is labelled as Assertion (A) and the other is labelled as Reason (R)

Assertion (A): Heat of neutralisation of

HF

(aq.) with

{NaOH}

(aq.) is greater than

13.7 \mathrm{~Kcal}

.

Reason (R): Generally some heat is consumed in the ionisation of weak acid.
On the basis of above statements choose the most appropriate option from the following options:

View answer and explanation

Correct option: A

Both (A) and (R) are correct but (R) is not the correct explanation of (A)

Option A is correct. The heat of neutralization of HF with NaOH is greater than 13.7 kcal because of the additional energy released due to the formation of hydrogen bonds. The reason is true, but it explains the lower heat of neutralization for weak acids, not the higher heat for HF.

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