Question

IUPAC name of hydroxybutyraldehyde is:
[A] 1-hydroxy butanal
[B] 2-hydroxy butanal
[C] 2-hydroxy butanol
[D] 2-hydroxy butyraldehyde

Answer 1

IUPAC is a worldwide accepted naming system. To name this compound, firstly identify the functional groups present here. Then count the number of carbon atoms here in the parent chain. Combining the two functional group names and the parent carbon chain will give you the IUPAC name of the given structure.

Complete answer:
We know that IUPAC nomenclature is a method of naming chemical compounds as recommended by the International Union of Pure and Applied Chemistry. There are certain steps that we have to follow while writing the IUPAC name of any compound.
Firstly, let us try to draw the structure of the given compound and number the carbon atoms in it.
For that, we have to know that the hydroxyl functional group is –OH and that for an aldehyde is –CHO. Here, we can see the prefix ‘but’ which means it has 4 carbon atoms i.e. the parent chain is a butane chain. A 4 membered chain with an aldehyde functional group is named butanal.
Also, while numbering the carbon atoms, we must remember that the aldehyde functional group is a higher priority group. Thus, we can draw the structure as-

We can see that we have a hydroxyl group at the second carbon position. We have already discussed that the parent chain here is named as butanal.
So, the IUPAC name of hydroxybutyraldehyde is 2-hydroxy butanal.

Therefore, the correct answer is option [B] 2-hydroxy butanal.

Note:
To write the IUPAC name of any compound, we should remember the basic principle that while naming any compound in its IUPAC name, we generally start with the number of carbons in the parent chain. In the suffix, we have the name of the functional group attached to the parent chain. The other groups which are present are the substituents.