Question

# Among the statements (a)-(d), the correct ones are:(A) Lithium has the highest hydration enthalpy among the alkali metals.(B) Lithium chloride is insoluble in pyridine.(C) Lithium cannot form ethynide upon its reaction with ethyne.(D) Both lithium and magnesium react slowly with ${{\text{H}}_{\text{2}}}{\text{O}}$ .

Hint: - The term ‘enthalpy of hydration’ or ‘hydration enthalpy’ is used to refer to the amount of energy which is released when one mole of gaseous ions is dissolved in water to form an infinitely dilute solution. The extent of hydration depends upon the size and charge of the ions, i.e., the extent of hydration depends on the charge density of ions.
- Covalent compounds are soluble in organic solvents.
- Alkali metals with small size cannot react with ethyne.
- Elements having a diagonal relationship have similar chemical behavior.

Charge density ${\text{ = }}\dfrac{{{\text{Charge}}}}{{{\text{Radius}}}}$