Question

Hydration enthalpy order of compound : $\mathrm{Li}{}^{+},\mathrm{Na}{}^{+},\mathrm{K}{}^{+},\mathrm{Rb}{}^{+}$ and $\mathrm{Cs}{}^{+}$

• A. $\mathrm{Li}{}^{+}>\mathrm{Na}{}^{+}>\mathrm{K}{}^{+}>\mathrm{Rb}{}^{+}>\mathrm{Cs}{}^{+}$
• B. $\mathrm{Li}{}^{+}<\mathrm{Na}{}^{+}<\mathrm{K}{}^{+}<\mathrm{Cs}{}^{+}<\mathrm{Rb}{}^{+}$
• C. $\mathrm{Na}{}^{+}<\mathrm{K}{}^{+}<\mathrm{Li}{}^{+}<\mathrm{Rb}{}^{+}<\mathrm{Cs}{}^{+}$
• D. $\mathrm{Na}{}^{+}<\mathrm{K}{}^{+}<\mathrm{Li}{}^{+}<\mathrm{Cs}{}^{+}<\mathrm{Rb}{}^{+}$

Answer 1

Answer: (A)

Hydration Energy $\propto$ Charge density of cation.