What is the molecular formula of ethanoic acid (acetic acid)?

The first member of the alkyne homologous series is:

Unsaturated hydrocarbons produce a yellow flame with a large amount of black smoke when burnt in oxygen. Give the reason.

How is scum formed?

Define the term 'structural isomerism'. Explain why propane cannot exhibit this property. Draw the structures of possible isomers of butane,$C_{4}H_{10}$.

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.