Answer 1

P = Phenol, Q = Acetone, R = Benzene, S = Isopropylbenzene

Answer 2

1. S to P + Q: Isopropylbenzene (S) undergoes cumene hydroperoxide process (oxidation with O$_2$/hν followed by acid hydrolysis with H$^\oplus$/H$_2$O) to yield phenol (P) and acetone (Q).

2. P to R: Phenol (P) is subjected to strong reduction with Red P/I$_2$. This reagent deoxygenates phenol to benzene (R). The KMnO$_4$/Δ step is a strong oxidation, but the subsequent strong reduction would convert any oxidized product back to benzene.

3. Q to S: Acetone (Q) is shown to convert to isopropylbenzene (S) using Zn, Δ followed by O$_3$/Zn, H$_2$O. This conversion is not chemically feasible with the given reagents. Ozonolysis is used for cleaving C=C bonds, which are absent in acetone. Therefore, this reaction sequence is inconsistent with standard organic chemistry. However, based on the initial structure provided, S is isopropylbenzene.

P (Phenol): Structure: C$_6$H$_5$-OH SMILES: Oc1ccccc1

Q (Acetone): Structure: CH$_3$-CO-CH$_3$ SMILES: CC(=O)C

R (Benzene): Structure: C$_6$H$_6$ SMILES: c1ccccc1

S (Isopropylbenzene): Structure: C$_6$H$_5$-CH(CH$_3$)$_2$ SMILES: CC(C)c1ccccc1

The reaction Q -> S is chemically unsound as written.

Answer:

P: Phenol (C$_6$H$_5$-OH) Q: Acetone (CH$_3$-CO-CH$_3$) R: Benzene (C$_6$H$_6$) S: Isopropylbenzene (C$_6$H$_5$-CH(CH$_3$)$_2$)

The reaction Q --(1) Zn, Δ ; (2) O$_3$/Zn, H$_2$O--> S is not a valid chemical transformation.