More practice questions

3. Q3. Which method on this page turns an alkyl halide into a primary amine with no secondary or tertiary amine mixed in, and keeps the number of carbons?

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   Gabriel phthalimide synthesis: the phthalimide anion is alkylated only once, and alkaline hydrolysis then sets free the primary amine (NCERT page 264; reasoned). Ammonolysis may still give a mixture even with excess ammonia, although the primary amine is favoured, and the nitrile route adds a carbon.

4. Q4. Which amide gives phenylmethanamine (benzylamine), C₆H₅CH₂NH₂, by Hofmann bromamide degradation?

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   2-Phenylethanamide, C₆H₅CH₂CONH₂: the amine has one carbon less than the amide, so the amide needs eight carbons for the seven-carbon amine (reasoned from NCERT page 264).

5. Q5. Write the equation for setting free ethanamine from ethylammonium chloride with sodium hydroxide.

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   CH₃CH₂NH₃⁺Cl⁻ + NaOH → CH₃CH₂NH₂ + H₂O + NaCl (reasoned from NCERT page 263).

6. Q6. Show how 1-bromopropane can be turned into butan-1-amine.

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   CH₃CH₂CH₂Br with ethanolic NaCN gives butanenitrile, CH₃CH₂CH₂CN; LiAlH₄ or H₂/Ni then reduces it to CH₃CH₂CH₂CH₂NH₂, one carbon more than the halide (reasoned from NCERT pages 263–264).