Glucose and gluconic acid on oxidation with dilute nitric acid forms saccharic acid. This reaction confirms that glucose contains

• A

  four primary alcoholic groups
• B

  two primary alcoholic groups
• Correct answer
  C

  one primary alcoholic groups
• D

  five hydroxyl groups

Solution

Only one $-\mathrm{CH}_2-\mathrm{OH}$ convert into $-\mathrm{COOH}$, confirm presence of one primary alcoholic.

Hence, the correct answer is option: 'C'.