LEARNATHON
III

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### Theory:

Let us try to name some of the other classes of organic compounds using IUPAC rules:

1.

Step 1: According to rule $$1$$, there is a three-membered carbon chain; hence, the root word is 'Prop'.

Step 2: According to rule $$2$$, all the bonds between carbon atoms are single bond, and thus the primary suffix is ‘ane’.

Step 3: According to rule $$3$$, the carbon chain is numbered from the end closest to the $$-OH$$ group that has the lowest locant number, as shown below

Numbering of the carbon chain

Step 4: The locant number is $$1$$ for the $$-OH$$ group, and hence the secondary suffix is ‘$$-1-ol$$’.

Note: According to rule $$5$$, when the primary and secondary suffixes are combined, the primary suffix's terminal 'e' is removed.

Hence, the name of the given compound is $$\text{Prop + ane + (-1-ol) = Propan-1-ol}$$.

2.

Step 1: According to rule $$1$$, there is a two-membered carbon chain; hence, the root word is 'Eth'.

Step 2: According to rule $$2$$, all the bonds between carbon atoms are single bonds, and thus the primary suffix is ‘ane’.

Step 3: The given compound contains carboxylic acid group ($$-COOH$$), and hence the secondary suffix is 'oic acid'.

Note: According to rule $$5$$, when the primary and secondary suffixes are combined, the primary suffix's terminal 'e' is removed.

Hence, the name of the given compound is $$\text{Eth + ane + oic acid = Ethanoic acid}$$.

3.

Step 1: According to rule $$1$$, there is a two-membered carbon chain; hence, the root word is 'Eth'.

Step 2: According to rule $$2$$, all the bonds between carbon atoms are single bond, and thus the primary suffix is ‘ane’.

Step 3: The given compound contains an aldehyde group ($$-CHO$$), and hence the secondary suffix is 'al'.

Note: According to rule $$5$$, when the primary and secondary suffixes are combined, the primary suffix's terminal 'e' is removed.

Hence, the name of the given compound is $$\text{Eth + ane + al = Ethanal}$$.

4.

Step 1: According to rule $$1$$, there is a four-membered carbon chain; hence, the root word is 'But'.

Step 2: According to rule $$2$$, all the bonds between carbon atoms are single bonds, and thus the primary suffix is ‘ane’.

Step 3: The given compound contains ketone group ($$-C=O$$), and hence the secondary suffix is 'one'.

Step 4: The numbering of carbon chain occurs in such a way that the lowest possible number is given to the functional group in the chain.

So, its locant number is $$2$$. Thus, the suffix is ‘$$2-one$$’.

Numbering of the carbon chain

Note: According to rule $$5$$, when the primary and secondary suffixes are combined, the primary suffix's terminal 'e' is removed.

Hence, the name of the given compound is $$\text{But + ane + (-2-one) = Butan-2-one}$$.

5.

Step 1: According to rule $$1$$, there is a four-membered carbon chain; hence, the root word is 'But'.

Step 2: According to rule $$2$$, all the bonds between carbon atoms are single bonds, and thus the primary suffix is ‘ane’.

Step 3: The given compound contains halogen group ($$Cl$$), and hence the prefix is 'chloro'.

Step 4: According to rule $$6$$, the substituent is a halogen group compound located at the first carbon atom.

The numbering of carbon chain occurs in such a way that the lowest possible number is given to the functional group in the chain.

Numbering of the carbon chain

So, its locant number is $$1$$. Thus, the prefix is ‘$$1-chloro$$’.

Hence, the name of the given compound is $$\text{1-chloro + But + ane = 1-Chloro butane}$$.

The below are some of the IUPAC names of various classes of compound: