General Organic Chemistry Question 9
Question 9 - 2024 (01 Feb Shift 2)
Following Kjeldahl’s method, $1 \mathrm{~g}$ of organic compound released ammonia, that neutralised $10 \mathrm{~mL}$ of $2 \mathrm{MH}{2} \mathrm{SO}{4}$. The percentage of nitrogen in the compound is _________ $%$.
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Answer (56)
Solution
Formula: Mole mole concept
$\mathrm{H}{2} \mathrm{SO}{4}+2 \mathrm{NH}{3} \rightarrow\left(\mathrm{NH}{4}\right){2} \mathrm{SO}{4}$
Millimole of $\mathrm{H}{2} \mathrm{SO}{4} \rightarrow 10 \times 2$
So Millimole of $\mathrm{NH}_{3}=20 \times 2=40$
Organic $\rightarrow \mathrm{NH}_{3}$
Compound 40 Millimole
$\therefore$ Mole of $N=\frac{40}{1000}$
wt. of $\mathrm{N}=\frac{40}{1000} \times 14$
$%$ composition of $\mathrm{N}$ in organic compound
$=\frac{40 \times 14}{1000 \times 1} \times 100$
$=56 %$
