Single Choice

Hydrogen bonds are formed in many compounds e.g., $$H_2O, HF \ and \ NH_3$$. The boiling point of such compounds depends to a large extent on the strength of the hydrogen bond and the number of hydrogen bonds. The correct decreasing order of the boiling points of the above compounds is :

A$$HF > H_2O > NH_3$$
B$$H_2O > HF > NH_3$$
Correct Answer
C$$NH_3 > HF > H_2O$$
D$$NH_3 > H_2O > HF$$

Solution

Strength of hydrogen bonding depends on the size and electronegativity of the atom.

Smaller the size of the atom, greater is the electronegativity and hence stronger is the $$H-$$bonding. Thus, the order of strength of H-bonding is $$H...F > H...O > H...N$$.

But each $$HF$$ molecule is linked only to two other $$HF$$ molecules while each $$H_2O$$ molecule is linked to four other $$H_2O$$ molecules through $$H-$$bonding.

Hence, the decreasing order of boiling points is $$H_2O > HF > NH_3$$.

Hence, the correct option is B.

SIMILAR QUESTIONS

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Strongest hydrogen bond is present in:

Chemical Bonding

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Chemical Bonding

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Chemical Bonding

Which of the following hydrogen bonds are strongest in vapour phase?

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Define hydrogen bond. Is it weaker or stronger than the Van der Waals forces?

Chemical Bonding

Which of the following has strongest bond?

Chemical Bonding

Among NH3,H2O,HF and H2S which have the highest magnitude of hydrogen bonding?

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