An aldehyde as well as a ketone can be represented by the same molecular formula,say $C_{3}H_{6}O$. Write their structures and name them. State the relation between the two in the language of science.

The structural formula of benzene is:

$A$ gas is evolved when ethanol reacts with sodium. Name the gas evolved and also write the balanced chemical equation of the reaction involved.

Which compound has the molecular formula $CH_{3}CHO$?

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 is the difference between two consecutive members in a homologous series of alkanes in terms of:
$(i)$ molecular mass.
$(ii)$ number of atoms of elements.