Question

Although dissolution of $N{H}_{4}Cl$ in water is endothermic but $\Delta S$ is

• A. +ve
• B. -ve
• C. zero
• D. none

Answer 1

The correct option is A +ve

Dissolution of $N{H}_{4}Cl$ in water:
There is a final solution, that is the water molecules pull apart the ammonium chloride lattice as a result of dipole - dipole interactions of the charged ions in the lattice in a reaction called hydration - the $N{H}_{4}Cl$ dissolves to yield $[N{H}_4{]}^{+}$ and $[Cl{]}^{-}$ ions
$N{H}_{4}Cl\left(s\right)\to \left[N{H}_4{]}^{+}\right(aq)+[Cl{]}^{-}\left(aq\right)$
here as no of ions in solution increases so entropy of system increases & $\Delta S$ is $+ve$.