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EEJ MAIN Chemistry QUESTION #7181
Question 1
A certain compound has a molecular mass of $180$. Upon acylation with $CH_{3}COCl$, its molecular mass increases to $390$. Determine the total number of amino groups present in each molecule of the original compound.
  • 2
  • 5✔️
  • 4
  • 6
Correct Answer Explanation
The change in molecular mass during acylation helps determine the number of functional groups.
  • Each acylation ($R-NH_{2} \rightarrow R-NHCOCH_{3}$) replaces one $H$ (mass 1) with an acetyl group $CH_{3}CO$ (mass 43).
  • Net mass increase per amino group = $43 - 1 = 42$ units.
  • Total mass increase = $390 - 180 = 210$ units.
  • Number of amino groups = $210 / 42 = 5$.