Question

Hydrides of group-16 elements show volatility in the order : $H_2O > H_2S > H_2Se > H_2Te$ Electronegativity of group-16 elements increases down the group from oxygen to tellurium.

• A. If both assertion and reason are true and reason is the correct explanation of assertion
• B. If both assertion and reason are true but reason is not the correct explanation of assertion
• C. If assertion is true but reason is false
• D. If both assertion and reason are false

Answer 1

Answer: (D)

If both assertion and reason are false

Answer 2

Hydrides of group-16 elements show volatility in the order : HS > HSe > HTe > HO Oxygen is most electronegative than other elements of group-16, it undergoes hydrogen bonding. Due to strong intermolecular hydrogen bonding in HO, it shows lowest volatility. As the size of the atom increases regularly from sulphur to tellurium, van der Waals??forces of attraction increase and hence volatility decreases from HS to HTe.