Q. An organic compound $X\$gives a red precipitate on heating with Fehling’s solution. Which one of the following reactions yields $X$ as a major product?
A) $HCHO\ \underset{(ii)H_{2}O}{\overset{(i)CH_{3}MgI\ \ \ }{\rightarrow}}$
B) $C_{2}H_{5}Br + AgOH\ \overset{\ \ \ \mathrm{\Delta}\ \ \ }{\rightarrow}$
C) $2C_{2}H_{5}Br + Ag_{2}O\overset{\ \ \ \ \mathrm{\Delta}\ \ \ \ }{\rightarrow}$
D) $C_{2}H_{2} + \ H_{2}O\ \underset{\begin{array}{r}
1\%\ HgSO_{4} \\
60^{0}C
\end{array}}{\overset{{\ \ \ \ \ \ 40\%\ H}_{2}{SO}_{4}\ \ \ \ }{\rightarrow}}$
Explanation
(d)
$C_{2}H_{2} + \ H_{2}O\underset{1\% HgSO_{4}}{\overset{{\ \ \ \ \ 40\%\ H}_{2}{SO}_{4}\ \ \ \ \ }{\rightarrow}}CH_{3}CHO$
acetaldehyde
Acetaldehyde + Fehling’s solution $\overset{\ \ \ \ \ \mathrm{\Delta}\ \ \ \ \ \ }{\rightarrow}$ Cuprous oxide
(Red ppt.)
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.