AIIMS2017Chemistryp Block Elements (Group 15, 16, 17 & 18)
Assertion : Hydrides of group-16 elements show volatility in the order: H ₂ O > H ₂ ~S > H ₂ Se > H ₂ Te Reason : Electronegativity of group-16 elements increases down the group from oxygen to tellurium.
Options
- AIf both assertion and reason are true and reason is the correct explanation of assertion.
- BIf both assertion and reason are true but reason is not the correct explanation of assertion.
- CIf assertion is true but reason is false.
- DIf both assertion and reason are false.
Correct answer
D. If both assertion and reason are false.
Step-by-step solution
Hydrides of group-16 elements show volatility in the order : H ₂ ~S > H ₂ Se > H ₂ Te > H ₂ O Oxygen is most electronegative than other elements of group-16, it undergoes hydrogen bonding. Due to strong intermolecular hydrogen bonding in H ₂ O , 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 H ₂ ~S to H ₂ Te .