Multiple Choice

Hydrogen bonding plays a central role in the following phenomena :

AIce floats in water.
Correct Answer
BHigher Lewis basicity of primary amines than tertiary amines in aqueous solutions.
Correct Answer
CFormic acid is more acidic than acetic acid.
DDimerisation of acetic acid in benzene.
Correct Answer

Solution

(A) Ice has cage-like structure in which each water molecule is surrounded by four other water molecules tetrahedrally through hydrogen bonding. Due to this, density of ice is less than water and it floats in water.

(B) $$R- NH_2 + H - OH \rightleftharpoons R - \overset{\bigoplus }{N}H_3 + OH^-$$
$$(I)$$

$$(R)_3 N+H - OH \rightleftharpoons (R)_3 - \overset{\bigoplus }{N}H+OH^-$$
$$(II)$$

The cation $$(I)$$ more stabilized through hydrogen bonding than cation $$(II)$$. So, $$R-NH_2$$ is better base than $$(R)_3N$$ in aqueous solution.

(C) Formic acid is more acidic because it has lesser number of alkyl groups attached and hence, lesser the +I effect of alkyl groups.

(D) Acetic acid exists as a dimer because of Hydrogen bonding as shown in the diagram.

Hence, option A, B and D are correct.

SIMILAR QUESTIONS

Chemical Bonding

The low density of ice compared to water is due to:

Chemical Bonding

Statement 1 : Conc $$\mathrm{H}_{2}\mathrm{S}\mathrm{O}_{4}$$ is a low volatility and viscos nature acid. Statement2: lt is due to Hydrogen bonding.

Chemical Bonding

Identify the correct statement(s) given below. (a) $$O_2$$ is paramagnetic. (b) $$H_2O$$ is liquid while $$H_2S$$ is gas under given conditions. (c) Boiling point of $$H_2O$$ is abnormally high.

Chemical Bonding

The correct order of boiling point is:

Chemical Bonding

The electronegativities of nitrogen and chlorine are almost same. However, $$NH_3$$ exists as liquid whereas $$HCl$$ as gas due to __________ between the molecules of $$NH_3$$.

Chemical Bonding

In solid ice, oxygen atom is surrounded

Chemical Bonding

Hydrogen halide with the highest boiling point is:

Chemical Bonding

Which of the following observations can be explained on the basis of hydrogen bonding? (i) $$H-F$$ has higher boiling point than other halogen acids. (ii) $$H_2O$$ has highest boiling point among hydrides of group 16 elements. (iii) $$NH_3$$ has lower boiling point than $$PH_3$$.

Chemical Bonding

The ice floats on water because:

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