$A$ molecule of ammonia has the formula $NH_{3}$. Predict the total number of bonds present around the nitrogen atom.

What is the common name of ethanal?

On dropping a small piece of sodium in a test tube containing carbon compound $X$ with molecular formula $C_{2}H_{6}O$,a brisk effervescence is observed and a gas $Y$ is produced. On bringing a burning splinter at the mouth of the test tube,the gas evolved burns with a pop sound. Identify $X$ and $Y$. Also,write the chemical equation for the reaction. Write the name and structure of the product formed when you heat $X$ with excess concentrated sulphuric acid.

What are soaps chemically? How do they differ from synthetic detergents? Explain the mechanism and the cleansing action of soap.

In which of the following compounds,$-OH$ is the functional group?

Which biopolymer was first used for post-operative stitches?