Question

Sweetest sugar among the naturally occurring sugar is
A) Glucose
B) Fructose
C) Sucrose 
D) Saccharine

Answer 1

Hint: In this question, we have asked about sweetest natural sugar. As we know saccharine is an artificial sugar. Sucrose is a 50:50 mixture of fructose and glucose and fructose is a fruit sugar which is sweeter than glucose.

Complete answer:
In this question we have asked about the sweetest natural sugar, and the options are glucose, fructose, sucrose and saccharin. Sweetness is a basic taste most commonly perceived when eating foods rich in sugars.
A sugar is a polyalcohol with at least one of them is either an aldehyde or a ketone.
> Our 1st option is glucose which is a simple sugar with the molecular formula $C_6H_{12}O_6$. Glucose is the most abundant monosaccharide, a subcategory of carbohydrates. Sweetness of glucose is 0.8.

> Fructose - The sweetness of fructose is due to its 6 membered ring form structure. The 5-membered ring form tastes about the same as glucose but sweeter than glucose. So, fructose is sweeter than glucose. Sweetness of fructose is 1.71-1.75. Fructose, or fruit sugar, is a simple monosaccharide having one ketone group. It is found in many plants, where it is often bonded to glucose to form the disaccharide.

> Sucrose - It is a 50:50 mixture of glucose and fructose. As we know glucose is less sweet than fructose so their mixture will be less sweet than fructose. So, sucrose is less sweet than fructose. Sweetness of sucrose is 1.

> Saccharine - It is a non-sugar sweetener. It is an artificial sugar and we have asked about natural sweetest sugar so saccharine is the wrong option. saccharine is 300-400 times sweeter than sugar.

Now, we know that option D) is wrong as glucose and sucrose is less sweet than fructose. So, the correct answer will be B) fructose.

Note: In this question, we have to keep in mind which sugar is natural and which is not because artificial sugar is very sweet even at low quantities or we can simply remember that fructose (fruit sugar) is the sweetest natural sugar.