Question

For the reversible process, the value of $\Delta S$ is given by the expression:

• A. $\frac{q_{rev}}{T}$
• B. $T-q_{rev}$
• C. $q_{rev}\times T$
• D. $q_{rev}-T$

Answer 1

The correct option is A $\frac{q_{rev}}{T}$

Entropy (S) is the measurement of disorder of the molecules or randomness. It is an extension property & is a stable function.

The change in entropy during a process is mathematically given as:

${\Delta }_r{S}^0=\sum S^0\left(products\right)-\sum S^0\left(reactants\right)$

$=\frac{q_{rev}}{T}=\frac{\Delta H}{T}$

$\therefore$ For reversible process, $\Delta S=\frac{q_{rev}}{T}$