Explain the common nomenclature of $(a)$ aldehyde compounds and $(b)$ ketone compounds.

(N/A) Aldehydes and ketones are often referred to by their common names.
$(a)$ Common names of Aldehydes:
$(i)$ The common names of aldehydes are derived from the common names of the corresponding carboxylic acids by replacing the terminal '-ic acid' with '-aldehyde'.
$(ii)$ These names often reflect the Latin or Greek origin of the source of the acid or aldehyde.
$(iii)$ The position of substituents in the carbon chain is indicated by Greek letters $\alpha, \beta, \gamma, \delta$,etc. The $\alpha$-carbon is the one directly linked to the $-CHO$ group,the $\beta$-carbon is the next,and so on.
$(iv)$ The carbon atom next to the $-CHO$ group is designated as $\alpha$: $\stackrel{\delta}{C}-\stackrel{\gamma}{C}-\stackrel{\beta}{C}-\stackrel{\alpha}{C}-CHO$.
Examples include $HCHO$ (Formaldehyde),$CH_3CHO$ (Acetaldehyde),and $\beta$-Bromobutyraldehyde.
$(b)$ Common names of Ketones:
$(i)$ Common names are obtained by naming the two alkyl or aryl groups attached to the carbonyl group $(>C=O)$ as two separate words in alphabetical order,followed by the word 'ketone'.
$(ii)$ For example,$CH_3COCH_3$ is dimethyl ketone (acetone) and $CH_3COC_2H_5$ is ethyl methyl ketone.