The spontaneous nature of a reaction is impossible if

  • A
    $\Delta H$ is $+ve$; $\Delta S$ is also positive
  • B
    $\Delta H$ is $-ve$; $\Delta S$ is also negative
  • C
    $\Delta H$ is $-ve$; $\Delta S$ is positive
  • D
    $\Delta H$ is $+ve$; $\Delta S$ is negative

Explore More

Similar Questions

Identify from the following the correct set of thermodynamic conditions for the reaction to be spontaneous at all temperatures.

When $\Delta H_{vap} = 30 \ kJ \ mol^{-1}$ and $\Delta S_{vap} = 75 \ J \ mol^{-1} \ K^{-1}$,then the temperature of vapour,at one atmosphere is . . . . $K$.

For the oxidation of ammonia at $298 \ K$,the standard enthalpy and standard entropy changes are $-382.64 \ kJ \ mol^{-1}$ and $-145.6 \ J \ K^{-1} \ mol^{-1}$ respectively. The standard Gibbs energy change for the same reaction at $298 \ K$ is $..... \ kJ \ mol^{-1}$.

The effect of temperature on the spontaneity of reactions is represented as follows:
Condition Details
$A$. $\Delta H: +, \Delta S: -$ $T$: any $T$,Spontaneity: Non-spontaneous
$B$. $\Delta H: +, \Delta S: +$ $T$: low $T$,Spontaneity: Non-spontaneous
$C$. $\Delta H: -, \Delta S: -$ $T$: low $T$,Spontaneity: Spontaneous
$D$. $\Delta H: -, \Delta S: +$ $T$: any $T$,Spontaneity: Spontaneous

Which of the above conditions are correctly matched?

If $\Delta H > 0$ and $\Delta S > 0$,the reaction can proceed spontaneously at:

Vedclass Products

For Students

Vedclass Test Series

Mock tests in real JEE/NEET style with performance analysis. 5-day free trial.

Start Free Trial
For Teachers

Exam Paper Generator

Generate Set A/B/C/D exam papers from 7.5L+ questions in 2 minutes. 3 chapters free.

Try Free
For Institutes

Online Exam Module

Live online exams with unlimited students, 360° analytics & white-label branding.

See Demo