When cyclohexanone reacts with dimethylamine in the presence of a catalytic amount of acid,water is continuously removed during the reaction. What is the product commonly called?

The compound formed when propanone is made to react with ethyl magnesium bromide followed by hydrolysis is

An organic compound $A$ reacts with methyl magnesium iodide to form an addition product,which on hydrolysis gives compound $B$. Compound $B$ gives a blue color in the Victor Meyer test. What are compounds $A$ and $B$ respectively?

Compound '$A$' (molecular formula $C_3H_8O$) is treated with acidified potassium dichromate to form a product '$B$' (molecular formula $C_3H_6O$). '$B$' forms a shining silver mirror on warming with ammoniacal silver nitrate. '$B$' when treated with an aqueous solution of $H_2NCONHNH_2 \cdot HCl$ and sodium acetate gives a product '$C$'. Identify the structure of '$C$.

The major product formed in the following reaction is:

The final product $A$ in the following reaction sequence is: