Question

The decreasing order of priority for the following functional groups is:

• A. (IV)> (I)>(II)>(III)
• B. (IV)> (I)>(III)>(II)
• C. (I)> (IV)>(III)>(II)
• D. (II)> (III)>(IV)>(I)

Answer 1

Answer: (C)

In case of polyfunctional compounds, one of the functional groups is closen as the principal group and the compound is named on that basis. The remaining functional groups, which are subordinate functional groups, are named as substituents using the appropriate prefixes. The decreasing order of priority of some functional groups is
$-COOH>-S{O}_{3}H>-COOR\text{ (ester) }>$
$-COCl\text{ (acylhalide) }>-CON{H}_2\text{ (amide) }>-C\equiv$
$N\text{ (nitriles) }>-CH=O\text{ (aldehyde) }>>C=O$
$\text{ (keto) }>-OH(\text{ alcohol })>-N{H}_2\text{ (amine) }>$
$>C=C<$ (alkene) $>-C\equiv C-($ alkyne $)$
The- R (alkyl group), Ph or $C_6{H}_5-$ (Phenyl), halogens (F, Cl, Br, I), $-N{O}_2$, alkoxy(-OR), etc., are always prefix substituents. Thus, a compound containing both an alcohol and a keto group is named hydroxyl alkanone since the keto group is preffered to the hydroxyl group

($a,b,c$, and d are in the decreasing preference order but written in IUPAC name:2-Amino-3hydroxy-4-oxopentan-1-oic acid