Question

Which of the following is a deliquescent substance?

• A. Glauber's salt
• B. Washing soda
• C. Calcium chloride
• D. Calcium sulphate

Answer 1

The correct option is C

Calcium chloride

An explanation for the correct option

(C) Calcium chloride

• The substances which on exposure to air, absorb moisture from it and change to a liquid state are called deliquescent substances.
• Example- Caustic soda $\left(\mathrm{NaOH}\right)$ and Calcium chloride $\left(\mathrm{Ca}{\left(\mathrm{Cl}\right)}_2\right)$.

The explanation for the incorrect options

(A) Glauber's salt

• The chemical formula of Glauber's salt is ${\mathrm{Na}}_2{\mathrm{SO}}_4.10{\mathrm{H}}_2\mathrm{O}$.
• A process where a compound loses its water of crystallization on exposure to dry air is called efflorescence.
• Glauber's salt ${\mathrm{Na}}_2{\mathrm{SO}}_4.10{\mathrm{H}}_2\mathrm{O}$ is an example of an efflorescent substance.

(B) Washing soda

• The chemical formula of Washing soda is ${\mathrm{Na}}_2{\mathrm{CO}}_3.10{\mathrm{H}}_2\mathrm{O}$.
• A process where a compound loses its water of crystallization on exposure to dry air is called efflorescence.
• Washing soda is ${\mathrm{Na}}_2{\mathrm{CO}}_3.10{\mathrm{H}}_2\mathrm{O}$. is an example of an efflorescent substance.

(D) Calcium sulphate

• Calcium sulphate is present in hydrated form as ${\mathrm{CaSO}}_4.2{\mathrm{H}}_2\mathrm{O}$.
• A process where a compound loses its water of crystallization on exposure to dry air is called efflorescence.
• Calcium sulphate.${\mathrm{CaSO}}_4.2{\mathrm{H}}_2\mathrm{O}$ is an example of an efflorescent substance.

Hence, c is the correct option as Calcium chloride $\left(\mathrm{Ca}{\left(\mathrm{Cl}\right)}_2\right)$ is an example of a deliquescent substance.