Given below are two statements, one is labelled as Assertion (A) and other as Reason (R) :
Assertion (A) : Invert sugar is more sweeter than sucrose.
Reason (R) : Invert sugar is obtained by the hydro

Question

Given below are two statements, one is labelled as Assertion (A) and other as Reason (R) :
Assertion (A) : Invert sugar is more sweeter than sucrose.
Reason (R) : Invert sugar is obtained by the hydrolysis of sucrose.
Select the correct answer from the codes given below.
Codes :

UnlockIAS · Accepted Answer

Correct — B, both (A) and (R) are true, but (R) is not the correct explanation of (A). Assertion: invert sugar really is sweeter than sucrose — it is an equimolar mixture of glucose and fructose, and fructose is the sweetest common sugar (about 1.7 times as sweet as sucrose), so the mixture out-sweetens sucrose. Reason: invert sugar is genuinely obtained by hydrolysing sucrose (sucrose + water → glucose + fructose, catalysed by the enzyme invertase or by acid) — also true. But the reason invert sugar tastes sweeter is the free fructose it contains, not the mere fact that it was made by hydrolysis; R states the method of preparation, not the cause of the extra sweetness. Hence both are true, yet R does not explain A.

Why the other options are wrong — (a) R (how invert sugar is made) is true but does not explain WHY it is sweeter — the extra sweetness is due to fructose, not to the hydrolysis process — so R is not the correct explanation.  (c) R is true — invert sugar really is produced by the hydrolysis of sucrose into glucose and fructose.  (d) A is true — invert sugar is sweeter than sucrose because of its fructose content.

Concept: Sucrose is a disaccharide of glucose and fructose. Its acid or enzymatic (invertase) hydrolysis yields an equimolar glucose–fructose mixture called invert sugar. The name comes from the inversion of optical rotation — sucrose is dextrorotatory, but the product mixture is net levorotatory because fructose is strongly levorotatory. Because free fructose is much sweeter than sucrose, invert sugar is sweeter and also resists crystallisation.

State PCS 2020 Q105 — Science & Technology PYQ with Answer

State PCS 2020 Q105 — Science & Technology PYQ with Answer