What is the name of this compound?
ethanal
ethylamine
ethanoic acid
methyl ethanoate

Answer: ethylamine
Explanation: The given compound contains a -[tex]NH_2[/tex] functional group which represents amines.
Also the compound contains two carbon atoms and thus the word root is -eth. As one of the hydrogen from ethane[tex]C_2H_6[/tex] is missing, the name changes to ethyl [tex]C_2H_5[/tex].
The naming starts with the longest carbon chain and ends with the functional group.
Thus the name is ethylamine.
-al is used for aldehydes. -oic acid is used for carboxylic acids and -oate is used for esters.