Difference in copper oxide mass indicates non-reducing sugar

Steps:

• Mass after direct Benedict's test measures reducing sugar.
• Mass after hydrolysis and Benedict's test measures total sugar (reducing + non-reducing).
• Non-reducing sugar = total mass - reducing mass.
• Compare differences: A (20-20=0), B (45-30=15), C (55-50=5), D (75-65=10).

Why B is correct:

• Largest difference (15) shows most non-reducing sugar hydrolyzed to reducing form.

Why the others are wrong:

• A: Zero difference means no non-reducing sugar.
• C: Small difference (5) means less non-reducing sugar than B.
• D: Difference (10) is less than B's 15.

Final answer: B