Why racimic mixture is optically inactive?

what is optical centre?

An optically active amide (A)C_5H_(11)NO on acid hydrolysis gives an acid and NH_3 . When (A) is treated with bromide and alkali a compound is obtained which one treatment with nitrous acid gives an optically active alcohol and nitrogen. The alcohol gives positive iodoform test. What is the structure of A and show the reactions involved.

What is optical communication?

Give reasons for the following: (+-) 2-Butanol is optically inactive

What is APC mixture?

Write the structure of D(+) Glylceraldehyde. Is this optically acitve?

What is racemic mixture? Give one example.

Explain the following terms: optical activity