A chemist has 4 samples of artificial sweetener A, B, C and D. To identify these samples, he performed certain experiments and noted the following observations:
(i) A and D both form blue-violet colour with ninhydrin.
(ii) Lassaigne extract of C gives positive test and negative test.
(iii) Lassaigne extract of B and D gives positive sodium nitroprusside test.
Based on these observations which option is correct?
(i) A and D both form blue-violet colour with ninhydrin.
(ii) Lassaigne extract of C gives positive test and negative test.
(iii) Lassaigne extract of B and D gives positive sodium nitroprusside test.
Based on these observations which option is correct?
- (A)A : Aspartame; B : Alitame; C : Saccharin; D : Sucralose
- (B)A : Aspartame; B : Saccharin; C : Sucralose; D : Alitame✓ Correct
- (C)A : Alitame; B : Saccharin; C : Aspartame; D : Sucralose
- (D)A : Saccharin; B : Alitame; C : Sucralose; D : Aspartame
Answer: (B)
Solution
The ninhydrin colour appears for A and D, marking the two sweeteners with a free amino-acid grouping, aspartame and alitame. The sodium nitroprusside test detects sulfur and is positive for B and D; since alitame carries sulfur as well as the amino grouping, D must be alitame, which leaves A as aspartame. The remaining sulfur-positive sample, B, is then saccharin, and C, whose Lassaigne extract shows chlorine through the silver nitrate test, is sucralose. This gives A aspartame, B saccharin, C sucralose and D alitame.
JEE Main · 2020 · 09 Jan 2020 · Shift 1 · Single correct option