Statement I: The boiling points of the following hydrides of group 16 elements increases in the order: H2O

Question

Statement I: The boiling points of the following hydrides of group 16 elements increases in the order: H2O < H2S < H2Se < H2Te Statement II: The boiling points of these hydrides increase with increase in molar mass. In the light of above statements, choose the most appropriate answer from the options given below:

KollegeApply · Accepted Answer

Both statement I and statement II are incorrect. Explanation: The boiling points of group 16 hydrides actually do not increase in the order H2O < H2S < H2Se < H2Te. Water (H2O) has an abnormally high boiling point due to strong intermolecular hydrogen bonding, so it boils at a much higher temperature than H2S despite having much lower molar mass. For the rest (H2S, H2Se, H2Te), boiling points increase with increasing molar mass due to stronger van der Waals forces. Therefore, Statement I is incorrect, as it wrongly states the boiling point order, but Statement II is correct because boiling points increase with molar mass except for the anomaly of water at the start of the group.

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