Question

An organic compound $X$ on analysis gives $24.24$ per cent carbon and $4.04$ per cent hydrogen. Further, sodium extract of $1.0g$ of $X$ gives $2.90g$ of silver chloride with acidified silver nitrate solution. The compound $X$ may be represented by two isomeric structures $Y$ and $Z$. $Y$ on treatment with aqueous potassium hydroxide solution gives a dihydroxy compound while $Z$ on similar treatment gives ethanal. Find out the molecular formula of $X$ and gives the structure of $Y$ and $Z$

Answer 1

Mass of chlorine in $1.0gX=\frac{35.5}{143.5}\times 2.9=0.717g$
Now, the empirical formula can be derived as :

	C	H	Cl
% wt :	24.24	4.04	71.72
Mole :	2	4	2
Simple ratio :	1	2	1

$\Rightarrow$ Empirical formula $=C{H}_{2}Cl$.
Because $X$ can be represented by two formula of which one gives a dihydroxy compound with $KOH$ indicates that $X$ has two chlorine atoms per molecule.
$\Rightarrow X=C_2{H}_{4}Cl$, with two of its structural isomers.
$\underset{I}{Cl-C{H}_2-C{H}_2-Cl}$ and $\underset{II}{C{H}_3-CHC{l}_2}$
On treatment with $KOH$, $1$ will give ethane-$1,2$-diol, hence it is $Y.Z$ on treatment with $KOH$ will give ethanal as