Consider the following four amines:
(I) $CH_{3} NH_{2}$
(II) $(CH_{3})_{2} NH$
(III) $(CH_{3})_{3} N$
(IV) $NH_{3}$
In the gas phase, how many of these amines have a basic strength greater than that of methylamine ( $CH_{3} NH_{2}$ )?

Question

Consider the following four amines:

(I) $CH_{3} NH_{2}$

(II) $(CH_{3})_{2} NH$

(III) $(CH_{3})_{3} N$

(IV) $NH_{3}$

In the gas phase, how many of these amines have a basic strength greater than that of methylamine ( $CH_{3} NH_{2}$ )?

TestHub · Accepted Answer

The basic strength in the gas phase depends on the +I effect of alkyl groups. More alkyl groups increase electron density on nitrogen, enhancing basicity.

(I) CH₃NH₂: Reference.

(II) (CH₃)₂NH: Two +I groups, more basic than CH₃NH₂.

(III) (CH₃)₃N: Three +I groups, more basic than CH₃NH₂.

(IV) NH₃: No +I groups, less basic than CH₃NH₂.

Thus, (II) and (III) are more basic than methylamine. Count = 2.

Chemistry - GOC Question with Solution | TestHub

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