How to synthesize N-methylpropanamide with a acid anhydride

See attached picture.

Explanation:

Hello.

In this case, since the synthesis of amides via anhydride requires its reaction with the N-radical primary amine, as it is required to yield N-methylpropanamide, the reactants must be propanoic anhydride and methylamine in order to yield the aforementioned amide as well as propanoic acid as a side product.

This reaction is shown on the attached picture.

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substituting a hydrogen atom with a halogen in a hydrocarbon:

- the single bond remains single. a is wrong.

- the bond with hydrogen is as strong as with a halogen. c is wrong

- a hydrocarbon is saturated if there is no double bond. we do not know that so d is wrong.

- carbon will always have four valence electrons. e is wrong.

by elimination, the correct answer is b. the boiling point of the new compound increases.