Pentan-2-amine is exhaustively methylated with excess CH3I, converted into the hydroxide with Ag2O/H2O, and heated. How many moles of CH3I are consumed per mole of amine, and what is the major hydrocarbon?

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JEE Advanced levelSingle correct optionDifficulty 3 of 3o4207

Pentan-2-amine is exhaustively methylated with excess $CH X_{3} I$ , converted into the hydroxide with $Ag X_{2} O$ / $H X_{2} O$ , and heated. How many moles of $CH X_{3} I$ are consumed per mole of amine, and what is the major hydrocarbon?

A2 mol; pent-2-ene
B3 mol; pent-1-ene
C3 mol; pent-2-ene
D2 mol; pent-1-ene

Answer: B

A primary amine

RNH X_{2}

has two N-H bonds and one lone pair, and takes three methyl groups to become

RN X^{+} (CH X_{3}) X_{3} I X^{-}

. Hofmann elimination of the hydroxide removes the most accessible hydrogen (the C1 methyl) rather than the C3 methylene, so pent-1-ene is major, with trimethylamine.

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Pentan-2-amine is exhaustively methylated with excess CHX3​I, converted into the hydroxide with AgX2​O/HX2​O, and heated. How many moles of CHX3​I are consumed per mole of amine, and what is the major hydrocarbon?

Answer: B

More questions on Saytzeff vs Hofmann products

Pentan-2-amine is exhaustively methylated with excess $CH X_{3} I$ , converted into the hydroxide with $Ag X_{2} O$ / $H X_{2} O$ , and heated. How many moles of $CH X_{3} I$ are consumed per mole of amine, and what is the major hydrocarbon?