Name the functional group present in the following compound: ${\mathrm{CH}}_3\mathrm{CHO}$

Name the functional group present in the following compound: (Aldehyde / Ketone)

${\mathrm{CH}}_3{\mathrm{COCH}}_3$

How would you name the following compound? 
${\mathrm{CH}}_3-{\mathrm{CH}}_2-\mathrm{Br}$

A : $1-$Bromoethane

B: 2- Bromoethane

C: 1-bromomethane

Enter your correct answer as A, B or C.

How would you name the following compound?

Define a homologous series. Give the name and structural formula of one homologue of the following: ${\mathrm{CH}}_3\mathrm{OH}$.