The product, when an alcoholic solution of sucrose is boiled with dilute hydrochloric acid or sulphuric acid is/are
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → 50% glucose and 50% fructose
Sucrose is a disaccharide in which one glucose unit and one fructose unit are joined by a glycosidic linkage between C1 of α-D-glucose and C2 of β-D-fructose. Boiling with a dilute mineral acid hydrolyses the glycosidic linkage, and each molecule of sucrose gives one molecule of glucose and one of fructose:
\( \displaystyle \ce{C12H22O11 + H2O} \xrightarrow{\ce{H^+}} \ce{C6H12O6}\,(\text{glucose}) + \ce{C6H12O6}\,(\text{fructose}) \)
The product is an equimolar mixture of the two sugars. Since glucose and fructose have the same formula, it is also 50% of each by mass.
Why the other options are incorrect
Option (1) Glucose only — Incorrect. Glucose alone is obtained from maltose or from starch; sucrose also contains a fructose unit.
Option (2) Fructose only — Incorrect. Half of each sucrose molecule is a glucose unit, so fructose cannot be the only product.
Option (4) 75% glucose and 25% fructose — Incorrect. One sucrose molecule gives one molecule of each sugar, so the two are always in a 1 : 1 ratio.
NCERT (2026-27 edition):
Sucrose
