Question

What are the hydrolysis products of sucrose?
A. Fructose + Fructose
B. Glucose + Glucose
C. Glucose + Galactose
D. Glucose + Fructose

Answer 1

Hint: Try to recall that sucrose is a disaccharide which on hydrolysis produces two monosaccharide units and also it is known that one of the monosaccharides is aldohexose and the other one is ketohexose. Now by using this you can easily find the correct option.

Complete step by step solution:
It is known to you that sucrose is a disaccharide and is also known as “cane sugar”.
Also, when sucrose is hydrolysed, it gets dissociated into two equimolar monosaccharides, of which one is aldohexose and the other one is ketohexose. Now by checking each option, you can easily answer:
In option A, both products are fructose and it is known to you that fructose is a ketohexose. So, this option is not correct.
In option B, both products are glucose and it is known to you that glucose is an aldohexose. So, option B is also not correct.
In option C, one of the products is glucose and the other one is galactose and it is known to you that both glucose and galactose are aldohexoses. So, this option is also not correct,
In option D, one of the products is glucose and the other one is fructose and it is known to us that glucose is an aldohexose and fructose is ketohexose. Hence, this is the correct option.
So, sucrose on hydrolysis gives an equimolar mixture of D- (+)-glucose and D- (-)-fructose. The reaction is:
${C_{12}}{H_{22}}{O_{11}} + {H_2}O \to {C_6}{H_{12}}{O_6} + {C_6}{H_{12}}{O_6}$
                                              D- (+)-glucose D- (-)-fructose
Hence, from above we can say that option D is the correct option.

Note: It should be remembered that sucrose is dextrorotatory in nature but after hydrolysis it gives dextrorotatory glucose and levorotatory fructose. This hydrolysis brings about a change in the sign of rotation from dextro(+) to laevo (-) and the product is known as invert sugar.