Test Index

Thermodynamics

Section: Chemistry

© examsnet.com

Question : 1 of 34

Marks: +1, -0

If

\Delta_r H^{\ominus}

\Delta_r S^{\ominus}

are standard enthalpy change and standard entropy change respectively for a reaction, the incorrect option is

[AP EAPCET 24 May 2025 S1]

$\Delta_r H^{\ominus}=$ negative; $\Delta_r S^{\ominus}=$ positive; spontaneous at all temperatures
$\Delta_r H^{\ominus}=$ negative; $\Delta_r S^{\ominus}=$ negative; non-spontaneous at low temperatures
$\Delta_r H^{\ominus}=$ positive; $\Delta_r S^{\ominus}=$ positive; non-spontaneous at low temperatures
$\Delta_r H^{\ominus}=$ negative; $\Delta_r S^{\ominus}=$ negative; spontaneous at low temperatures

Solution:

Statement given in option (b) is incorrect. Its correct form is,

The spontaneity of a reaction with a negative enthalpy change (exothermic) and a negative entropy change (decreasing disorder) depends on temperature.

When

\Delta H

is negative and

\Delta S

is negative the reaction is non-spontaneous at high temperature.

© examsnet.com

Go to Question:

Next Question