Question

When glucose reacts with bromine water, the main product is:
A. Acetic acid
B. Saccharic acid
C. Glyceraldehyde
D. Gluconic acid

Answer 1

Hint: Bromine water acts as the oxidizing agent it oxidizes the carbonyl group, it can be aldehydes and ketone. Glucose is also called dextrose, it is carbohydrate and monosaccharides, that is it does not hydrolyze further. It is found in fruits and honey and also it is found as major free sugar in the blood of many animals and humans. During reaction with bromine water the aldehyde group of glucose converted to carboxylic acid.

Complete step-by-step answer:
We have glucose which is having six carbon atoms, aldehyde carbon at top and alcoholic carbon at the end. We can make the structure of glucose as shown below,

Here, the aldehyde group at the top of glucose gets oxidized to carboxylic acid and gives D-gluconic acid.
We get acetic acid as a product from glucose on aerobic fermentation. It is a two stage process in which firstly glucose is converted to ethanol and then in the next step it is converted into acetic acid. There are processes when fatty acids are formed. It is a biological process when we are full of energy (ATP) then the extra glucose in our body gets converted to fatty acids. All the sugars are derived from glyceraldehyde thus we cannot convert glucose into glyceraldehyde.
Saccharic acid is obtained when aldehyde and alcoholic groups on glucose are oxidized to COOH this process takes place when we use a strong oxidizing agent like nitric acid.

Thus option (D) is correct.

Note: These types of questions need a very good knowledge of the structure of glucose. If anyone is familiar with the structure and the reagents then he or she can easily make the desired product from glucose. Many times cyclic structure and Haworth projection of glucose are needed like when glucose and fructose combines to make sucrose.