EasyChemistryHigh School (11–12)Organic Compounds with Functional Groups › AminesNumerical

A chemist treats 5.45 g of bromoethane (109 g/mol) with alcoholic potassium cyanide to make…

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A chemist treats $5.45\ \text{g}$ of bromoethane ( $109\ \text{g/mol}$ ) with alcoholic potassium cyanide to make propanenitrile, $\text{C}_3\text{H}_5\text{N}$ ( $55\ \text{g/mol}$ ). All of the halide reacts. The nitrile is then either boiled with dilute acid, to give propanoic acid ( $74\ \text{g/mol}$ ) and ammonia, or reduced to propan-1-amine ( $59\ \text{g/mol}$ ). Take every step at a yield of 100 %. Find the mass of propanenitrile, the mass of propanoic acid, the mass of ammonia formed in the hydrolysis ( $17\ \text{g/mol}$ ) and the mass of propan-1-amine.

Need a reminder? The key ideaShow

Silver cyanide gives an isocyanide and potassium cyanide gives a nitrile. A nitrile is reduced to a primary amine with one more carbon than the halide. An isocyanide is hydrolysed by acid to a primary amine and formic acid, and is reduced to a secondary amine. Nitrobenzene takes 6, 4 or 5 electrons in an acidic, neutral or alkaline medium, and each atom of zinc or tin gives 2 electrons.

The worked solution

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