Read the passage carefully and answer the questions.
Biomolecules are the organic compounds present as an essential constituents of living organisms in different cells. The molecules are generally termed as macromolecules, which are carbohydrates, enzymes, nucleic acids, amino acids and proteins etc. Carbohydrates are classified as sugars and non-sugars include sucrose, glucose, fructose, starch and cellulose. Enzymes are coordinated with various chemical reactions in nucleic acid. Nucleic acids are found in living organisms made up of proteins and natural polymers. Two types that are generally found in biological systems are DNA and RNA nucleic acid. Amino acids are bifunctional groups of carboxyl and amino groups. Proteins are a class of biologically important compounds. They are crucial to virtually all processes in living systems. Some of them are hormones, which serve as chemical messengers that coordinate certain biochemical activities.
Glucose when treated with Bromine water forms
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Gluconic acid
Glucose has an aldehyde group at C1, five –OH groups and a –\( \ce{CH2OH} \) group at C6. Bromine water is a mild oxidising agent: it oxidises only the –CHO group to –COOH and leaves the alcohol groups untouched. The product is a six-carbon acid, gluconic acid.
Why the other options are incorrect
Option (1) Saccharic acid — Incorrect. Saccharic acid, \( \ce{COOH-(CHOH)4-COOH} \), is formed with the strong oxidant nitric acid, which oxidises the primary alcohol group as well.
Option (3) Glyceric acid — Incorrect. Glyceric acid has only three carbon atoms; mild oxidation does not break the carbon chain of glucose.
Option (4) Glyceraldehyde — Incorrect. Glyceraldehyde is the three-carbon aldose; it is the reference compound for D/L configuration, not an oxidation product of glucose.
Note: It seems that there is a mistake in the original NTA paper, which prints “Amino acids are bifunctional groups of carboxyl and amino groups” in the passage when it should read “Amino acids are bifunctional compounds containing carboxyl and amino groups”. It also prints “Nucleic acids are found in living organisms made up of proteins and natural polymers” when it should read “Nucleic acids are natural polymers of nucleotides found in living organisms”, and “Enzymes are coordinated with various chemical reactions in nucleic acid” when it should read “Enzymes catalyse the chemical reactions in living systems”.
NCERT (2026-27 edition):
Glucose – …
