Question

1. What are vitamins? Name any two diseases caused by deficiency of vitamin A. Write the structure of (a) nucleoside (b) nucleotide
2. How are 1-nitropropane,2-nitropropane and 2-methyl-2-nitropropane distinguished from each other using nitrous acid?

Answer 1

Vitamins are defined as the organic substances which are required by the living beings for the maintenance of the body and to permit proportionate growth. Nucleoside contains only a nitrogenous base and a five carbon sugar whereas nucleotide contains nitrogenous bases, five carbon sugar and a phosphate group. 1-nitropropane,2-nitropropane and 2-methyl-2-nitropropane are distinguished on the basis of the color they produced on reaction with nitrous acid.

Complete answer:
Let us discuss each question one by one.

1. What are vitamins? Name any two diseases caused by deficiency of vitamin A. Write the structure of (a) nucleoside (b) nucleotide
   - From your chemistry lessons you have learned about the vitamins and about their benefits and diseases caused due to deficiency of vitamins and also about the structures of nucleoside and nucleotide.
   Vitamins are defined as the organic substances or an essential micronutrient which is required by the living beings for the maintenance of the body and to permit proportionate growth. It is needed for normal growth, cell function and development. Vitamins are required in small quantities for proper functioning but its deficiency can cause major problems in our body.
   The diseases that are caused due to deficiency of vitamins are as follows:
   (i) Dryness of hair and skin
   (ii) Night blindness
   As we know that nucleoside contains only a nitrogenous base and a five carbon sugar in their structure whereas nucleotide contains nitrogenous bases, five carbon sugar and a phosphate group in their respective structure. And the structure is given as:

2. How are 1-nitropropane,2-nitropropane and 2-methyl-2-nitropropane distinguished from each other using nitrous acid?
   - In case of 1- nitropropane (also known as primary nitro alkane), it react with nitrous acid it forms blue colored nitroso-nitro propane which further reacts with NaOH to produce red color solution.

- In case of 2-nitropropane, it reacts with nitrous acid to give blue colored nitro-nitroso propane. But here it does not react further with NaOH due to the absence of alpha hydrogen.

- In case of 2-methyl-2-nitropropane, it does not react with nitrous acid due to the absence of alpha hydrogen in 2-methyl-2-nitropropane.

Note:
Alpha hydrogen are those hydrogen which are directly bonded to alpha carbon. Alpha carbon refers to the first carbon atom that attaches to the functional group and the second carbon atom is known as beta carbon and the hydrogen attached with beta carbon is known as beta hydrogen.