Question

Which of the following orders are correct as per the properties mentioned against each?

(i)	\[\ce{As2O3 < SiO2 < P2O3 < SO2}\]	Acid strength.
(ii)	\[\ce{AsH3 < PH3 < NH3}\]	Enthalpy of vapourisation.
(iii)	\[\ce{S < O < Cl < F}\]	More negative electron gain enthalpy.
(iv)	\[\ce{H2O > H2S > H2Se > H2Te}\]	Thermal stability.

Answer 1

(i)	\[\ce{As2O3 < SiO2 < P2O3 < SO2}\]	Acid strength.
(iv)	\[\ce{H2O > H2S > H2Se > H2Te}\]	Thermal stability.

Explanation:

Acidic strength of oxides in a group decreases down the group and increases along a period from left to right.

Thermal stability of hydrides of group 16 decreases down the group.