Question

The IUPAC name of $ C{H_3} - O - CH(C{H_3}) - C{H_3} $ is:
A) 3-Methoxy propane
B) 2-Methyl methoxy ethane
C) 1-Methoxy-1-methyl ethane
D) Methoxy isopropane

Answer 1

Hint: IUPAC stands for International Union of Pure and Applied Chemistry. It is the world authority on the chemical nomenclature as well as terminology. Thus, IUPAC nomenclature is basically a method of naming organic compounds according to certain rules.

Complete answer:
 IUPAC provides consistency to the names of organic compounds. It enables every compound to possess a unique name, which otherwise is not plausible with the common names. The chemical structure of the given compound is shown below:

Now, let us have a look at the important rules that need to be followed during naming of a compound:
To determine the prefix or suffix of the compound name, recognise the functional group present in the compound (as listed in table).

Functional group	Prefix or Suffix
Alkane	-ane
alkene	-ene
Alkyne	-yne
Alcohol	-ol
Aldehyde	-al
Ketone	-one
Carboxylic acid	-oic acid
ester	-oate
ether	Alkoxy-
Haloalkane	Halo-

The given compound is an alkane so suffix in our case will be –ane. An ether functional group is also present so prefix will be Alkoxy-.
To determine the name of a compound, identify the longest and continuous chain of carbon containing the functional group and count the number of carbon atoms in the chain as shown in the table below.

Number of carbon atoms	Prefix
1	Meth-
2	Eth-
3	Prop-
4	But-
5	Pent-
6	Hex-
7	Hept-
8	Oct-
9	Non-
10	Dec-

In the given compound, the number of carbon atoms in the longest chain is 2. That means the prefix of alkane in our case is eth-.
Numbering of the carbons in the longest chain of carbon (Remember that If the organic molecule is not an alkane (and has a functional group) you have to initiate numbering such that the functional group is placed on the carbon having the lowest possible number).
In the given compound, we can number as shown below:

Check if there are any branched groups, name them and allocate the number of the carbon atom to which that group is linked. The branched groups must be mentioned before the name of the main chain in an alphabetical order.
In the given compound, either the group and methyl group present on the second carbon will be treated like a branched group. It will be written as 2-methyl methoxy before the main chain name.
Finally, combine the elements of the compound name in the specified order as: branched groups, prefix, suffix according to the functional group and its location along the longest carbon chain.
Therefore, the given compound will have IUPAC name as: 2-methyl methoxy ethane.
Hence, the correct answer is Option (B), the IUPAC name of $ C{H_3} - O - CH(C{H_3}) - C{H_3} $ is 2-Methyl methoxy ethane.

Note:
IUPAC nomenclature creates a standardized method to name the chemical compounds. Common nomenclature employs the older names for organic compounds rather than using the prefixes for the carbon chain. IUPAC nomenclature even provides certain rules for the naming of ions as well.