JEE PYQ: Hydrocarbons Question 3
Question 3 - 2021 (16 Mar Shift 2)
An unsaturated hydrocarbon X on ozonolysis gives A. Compound A when warmed with ammonical silver nitrate forms a bright silver mirror along the sides of the test tube. The unsaturated hydrocarbon X is:
(1) $\text{CH}_3-\text{C}=\text{C}-\text{CH}_3$ (with $\text{CH}_2\text{CH}_3$ substituents)
(2) Methylenecyclopropane ($\text{CH}_3$-substituted)
(3) $\text{HC}\equiv\text{C}-\text{CH}_2-\text{CH}_3$
(4) $\text{CH}_3-\text{C}\equiv\text{C}-\text{CH}_3$
Show Answer
Answer: (3)
Solution
As (A) compound gives positive Tollen’s test hence it may contain $-\text{CHO}$ (aldehyde group), or it can be HCOOH. So for the given option: (c) $\text{CH}_3\text{CH}_2\text{C}\equiv\text{CH} \xrightarrow{\text{Ozonolysis}} \text{CH}_3\text{CH}_2\text{COOH} + \text{HCOOH}$ (A) — gives positive Tollen’s test. The other options on ozonolysis give ketones which do not show Tollen’s test.
BETA
