Question

Write the structural formula for the IUPAC name: Pent-2-one

Answer 1

Hint: The structure of a molecule can be determined by following follows step:
1) Determine the parent chain
2) Add the functional groups and multiple bonds at the positions. Number the parent chain in such a way that the numbering satisfies the location of the substituent.
3) Finally, fill in all carbon with a hydrogen bond. Remember that carbon forms four bonds.


Complete Solution :
In drawing the structure of the molecule from the IUPAC nomenclature we will follow the following steps.
Step 1) in drawing the structure from the IUPAC name, let's first start with the parent chain. We are interested in determining the structure of pent-2-one.so, the parent chain in pent-2-one is pentane. Pent stands for the five .thus the pent-2-one includes a parent chain which contains five carbon atoms in the long carbon chain. The parent chain is as shown below:

Step 2) According to the given IUPAC name the compound has a ketone as a function group. The name suggests that the ketone or carbonyl groups are located at the two number carbon atoms. We have already numbered the parent chain. The carbonyl group would be placed on2 a number of carbon atom as shown below:

Step 3) now we have the basic structural skeleton for the pent-2-one. finally, fill in all hydrogen atoms on the carbon atom to satisfy their valency. Remember that each carbon forms four bonds. Thus the carbonyl carbon atom has already satisfied its valency. It does not form a bond with a hydrogen atom. The complete structure of pent-2-one is as follows:

So, we have determined the structure of pent-2-one.

Note: Note that, the numbering of the parent chain is always done in such a way the functional group gets the lowest number even the substituents get the higher number. Always remember that the IUPAC name of the compound is given as $\text{ Prefix + word root + Primary suffix + secondary suffix }$ .