Question

In the following compound, the least number of monochlorination is possible in

• A. ${\mathrm{CH}}_3{\mathrm{CH}}_2{\mathrm{CH}}_2{\mathrm{CH}}_2{\mathrm{CH}}_3$
• B. ${\mathrm{CH}}_3-\underset{\underset{{\mathrm{CH}}_3}{|}}{\mathrm{CH}}-{\mathrm{CH}}_2{\mathrm{CH}}_3$
• C. ${\mathrm{CH}}_3-\underset{\underset{{\mathrm{CH}}_3}{|}}{\stackrel{\stackrel{{\mathrm{CH}}_3}{|}}{\mathrm{C}}}-\mathrm{H}$
• D. ${\mathrm{CH}}_3-\stackrel{{\mathrm{CH}}_3}{\stackrel{|}{\underset{\underset{{\mathrm{CH}}_3}{|}}{\mathrm{C}}}}-{\mathrm{CH}}_3$

Answer 1

The correct option is D

${\mathrm{CH}}_3-\stackrel{{\mathrm{CH}}_3}{\stackrel{|}{\underset{\underset{{\mathrm{CH}}_3}{|}}{\mathrm{C}}}}-{\mathrm{CH}}_3$

The explanation for the correct option:

Option (D): ${\mathrm{CH}}_3-\underset{\underset{{\mathrm{CH}}_3}{|}}{\stackrel{\stackrel{{\mathrm{CH}}_3}{|}}{\mathrm{C}}}-{\mathrm{CH}}_3$

1. Chlorination with a single atom is known as monochlorination. This is accomplished by chlorinating the alkane in the presence of UV radiation.
2. Chlorination depends on the type of hydrogen whether it is primary, secondary, or tertiary.
3. All of the hydrogen in the given compound is of the same kind, i.e. primary hydrogen. Hence, the least monochlorination is possible.
4. Hence it is the correct option.

Explanation for incorrect option(s):

Option (A): ${\mathrm{CH}}_3{\mathrm{CH}}_2{\mathrm{CH}}_2{\mathrm{CH}}_3$

1. In the given compound there are different kinds of hydrogen present i.e. two primary hydrogens and two secondary hydrogens on which chlorination is possible.
2. Therefore, least monochlorination is not possible
3. Hence it is an incorrect option.

Option (B): ${\mathrm{CH}}_3-\underset{\underset{{\mathrm{CH}}_3}{|}}{\mathrm{CH}}-{\mathrm{CH}}_2{\mathrm{CH}}_3$

1. In the given compound there are three primary, one secondary and one tertiary hydrogen are present on which chlorination can occur.
2. Because, there are different types of hydrogen present, least monochlorination is not possible.
3. Hence, it is an incorrect option.

Option (C): ${\mathrm{CH}}_3-\stackrel{\stackrel{{\mathrm{CH}}_3}{|}}{\underset{\underset{{\mathrm{CH}}_3}{|}}{\mathrm{C}}}-\mathrm{H}$

1. In the given compound, there is one tertiary and three primary hydrogen present.
2. Because, there are different types of hydrogen, least monochlorination is not possible.
3. Hence, it is an incorrect option.

Therefore, the least monochlorination is only possible in ${\mathrm{CH}}_3-\underset{{\mathrm{CH}}_3}{\underset{|}{\stackrel{{\mathrm{CH}}_3}{\stackrel{|}{\mathrm{C}}}}}-{\mathrm{CH}}_3$.