An irreversible process occurring isothermally in an isolated system leads to

Considering entropy $(S)$ as a thermodynamic parameter,what are the necessary conditions for a process to be spontaneous?

For the reaction $H_2O_{(l)} \longrightarrow H_2O_{(g)}$ at $T=100^{\circ} C$ and $P=1 \ atm$,choose the correct option:

What is entropy?

For which one of the following reactions is the entropy change positive?

One mole of water at $100\,^{\circ}C$ is converted into steam at $100\,^{\circ}C$ at a constant pressure of $1\,atm$. The change in entropy is [heat of vaporisation of water at $100\,^{\circ}C = 540\,cal/g$].