Classification of Matter A.2 Classification of Organic Compounds (id: c2c49e738)

本题目来源于试卷: Classification of Matter A.2 Classification of Organic Compounds，类别为 IB化学

[单选题]
The structural formulr0yqfl459nx.8 h wlfa l4to7,, gng0t 1sso ooas of two compounds in a homologous series are shown.

Why does the boiling point of compound Y differ from that of compound X?

A. $Y$ has a higher boiling point because there are more atoms interacting via dispersion forces
B. $Y$ has a lower boiling point because there are more atoms interacting via dispersion forces
C. $Y$ has a higher boiling point because there are more atoms interacting via hydrogen bonds
D. $Y$ has a lower boiling point because there are more atoms interacting via hydrogen bonds


参考答案:  A


本题详细解析:
Explanation:

The two compounds are part of a homologous series because they have the same functional group but different hydrocarbon chains. Both compounds are alcohols, so interact via hydrogen bonding.

The $CH_2$ and $CH_3$ groups of the alkyl chains, however, interact via weaker dispersion forces, as they contain only non-polar bonds. Increasing the length of the alkyl chain does not affect the strength of hydrogen bonding, but the strength of the dispersion forces is increased. More heat energy is needed to separate molecules of Y, so the boiling point is higher.

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