Given below are the four isomeric compounds(P,Q,R, S)
Identify correct statements from below.
A. Q,R and S will give precipitate with 2, 4-DNP.
B. P and Q will give positive Bayer's test.
C. Q and R will give sooty flame.
D. R and S will give yellow precipitate with I₂/NaOH.
E. Q alone will deposit silver with Tollen's reagent
Choose the correct option.

Solution

Chemistry ma’am · 2 steps

Name the functional group in each isomer first, and then every test becomes a simple yes or no.

1. Identify the isomers. All four are C₉H₁₀O. P is CH₂=CH-CH(OH)-C₆H₅, an alcohol with a C=C. Q is C₆H₅CH₂CH₂CHO, an aldehyde. R is C₆H₅CH₂COCH₃, a methyl ketone. S is C₆H₅COCH₂CH₃, an ethyl ketone.

   Statement	What the test needs	Check	Verdict
   A. 2,4-DNP	a C=O group (aldehyde or ketone)	Q, R and S all have C=O	correct
   B. Baeyer's test	a C=C or C≡C bond	P has C=C, but Q has none	wrong
   C. Sooty flame	an aromatic ring (high C to H ratio)	Q and R both have a benzene ring	correct
   D. Iodoform	a CH₃CO⁻ or CH₃CH(OH)⁻ group	R has CH₃CO⁻, S has CH₃CH₂CO⁻	wrong
   E. Tollens' reagent	a -CHO group	only Q is an aldehyde	correct

2. So. Statements A, C and E are correct, and B and D are not. The answer is (d).

The idea to keep. Iodoform needs a CH₃CO⁻ or CH₃CH(OH)⁻ group, not just any ketone. Baeyer's test looks for C=C, and every compound with a benzene ring burns with a sooty flame.

Answer from the NTA final answer key. Solution by PrepWiser.