Question

A compound (\( x \)) with molar mass \( 108 \, \text{g mol}^{-1} \) undergoes acetylation to give a product with molar mass \( 192 \, \text{g mol}^{-1} \). The number of amino groups in the compound (\( x \)) is ______.

Answer 1

Correct Answer: 2

To determine the quantity of amino groups (\( x \)) in the compound, analyze the molar mass augmentation resulting from acetylation. Acetylation entails substituting a hydrogen atom on an amino group with an acetyl group (\( \text{CH}_3\text{CO} \)), thereby increasing the molar mass by \( 42 \, \text{g mol}^{-1} \) for each modified amino group.
1. Calculate the molar mass differential between the acetylated product and the precursor: \( 192 \, \text{g mol}^{-1} - 108 \, \text{g mol}^{-1} = 84 \, \text{g mol}^{-1} \).
2. Ascertain the number of acetyl groups introduced, given that each addition elevates the molar mass by \( 42 \, \text{g mol}^{-1} \): \( \frac{84 \, \text{g mol}^{-1}}{42 \, \text{g mol}^{-1}} = 2 \) amino groups.
This derived value of 2 aligns with the anticipated range of 2,2, validating the result.