Q.8Match the entries in Group I with the entries in Group II

The correct matching is:
P – (iv), Q – (i), R – (ii), S – (iii), so the right option is (A).​

Introduction

Matching the entries in Group I with the entries in Group II for Nylon, Natural rubber, Starch and Myoglobin is a classic polymer and biomolecule MCQ that appears in competitive chemistry and biology exams. Understanding which monomer or basic unit forms each macromolecule helps in quickly eliminating wrong options and choosing the correct matching pattern in such questions.​

Step‑by‑step matching of Group I and Group II

P) Nylon

• Concept: Common nylons such as nylon‑6,6 are synthetic polyamides formed by condensation polymerization of a diamine with a dicarboxylic acid.​

• Correct pairing:

  • Nylon‑6,6 is produced from hexamethylenediamine and adipic acid, so it is correctly matched with (iv) Adipic acid.​

• Why other options are wrong for P:

  • (i) Isoprene is a diene that polymerizes to give natural rubber, not nylon.​

  • (ii) Hexose is a six‑carbon sugar, unrelated to nylon synthesis.​

  • (iii) Amino acid is the monomer of proteins like myoglobin, not synthetic nylon.​

So, P – (iv) Adipic acid is correct.

Q) Natural rubber

• Concept: Natural rubber is a natural polymer obtained from latex, chemically described as poly‑cis‑isoprene.​

• Correct pairing:

  • Its fundamental repeating unit is isoprene, so Q must match (i) Isoprene.​

• Why other options are wrong for Q:

  • (ii) Hexose is a carbohydrate unit, not the building block of rubber.​

  • (iii) Amino acid forms proteins, not rubber.​

  • (iv) Adipic acid is involved in nylon‑6,6, not natural rubber.​

Thus, Q – (i) Isoprene is the only correct match.

R) Starch

• Concept: Starch is a storage polysaccharide in plants composed of the glucose polymers amylose and amylopectin.​

• Correct pairing:

  • Since starch is built from glucose, a six‑carbon sugar, it is a polymer of a hexose unit, so R pairs with (ii) Hexose.​

• Why other options are wrong for R:

  • (i) Isoprene forms polyisoprene (rubber), not starch.​

  • (iii) Amino acids are monomers of proteins, not carbohydrates like starch.​

  • (iv) Adipic acid is a dicarboxylic acid used in nylon, not a sugar monomer.​

Hence, R – (ii) Hexose is correct.

S) Myoglobin

• Concept: Myoglobin is a globular oxygen‑binding protein found in muscle; it is a single polypeptide chain composed of more than 150 amino acids with a heme group.​

• Correct pairing:

  • Being a protein, myoglobin’s polymeric chain is made of amino acids, so S corresponds to (iii) Amino acid.​

• Why other options are wrong for S:

  • (i) Isoprene is a hydrocarbon, not a protein monomer.​

  • (ii) Hexose is a carbohydrate, not the primary monomer of myoglobin.​

  • (iv) Adipic acid is used in nylon synthesis, not in forming myoglobin.​

Therefore, S – (iii) Amino acid is the correct match.

Evaluating the given options

The matches deduced are:

• P – (iv) Adipic acid

• Q – (i) Isoprene

• R – (ii) Hexose

• S – (iii) Amino acid

Now compare with the alternatives:

• (A) P‑iv, Q‑i, R‑ii, S‑iii – exactly matches all four correct pairings → correct answer.

• (B) P‑iv, Q‑i, R‑iii, S‑ii – wrongly swaps starch and myoglobin, pairing starch with amino acid and myoglobin with hexose.

• (C) P‑iv, Q‑iii, R‑ii, S‑i – misassigns natural rubber to amino acid and myoglobin to isoprene.

• (D) P‑ii, Q‑iv, R‑i, S‑iii – mismatches nylon with hexose, natural rubber with adipic acid, and starch with isoprene; only myoglobin is correctly linked with amino acid.

Thus, the correct option is (A) for the question “Match the entries in Group I with the entries in Group II: Nylon, Natural rubber, Starch, Myoglobin.”