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PUMPA - SMART LEARNING
எங்கள் ஆசிரியர்களுடன் 1-ஆன்-1 ஆலோசனை நேரத்தைப் பெறுங்கள். டாப்பர் ஆவதற்கு நாங்கள் பயிற்சி அளிப்போம்
Book Free DemoLet us try to name some of the linear and substituted hydrocarbons in a systematic manner using IUPAC rules:
1. \(CH_3-CH_2-CH_2-CH_2-CH_3\)
Step 1: According to rule \(1\), there is a five-membered carbon chain; hence, the root word is ‘Pent’.
Step 2: According to rule \(2\), all the bonds between carbon atoms are single bonds, and thus the suffix is ‘ane’.
So, the name of the given compound is \(\text{Pent + ane = Pentane}\).
2. ![4a.png](https://resources.cdn.yaclass.in/56a338cd-491b-449b-b169-30cf3da6625e/4aw300.png)
![4a.png](https://resources.cdn.yaclass.in/56a338cd-491b-449b-b169-30cf3da6625e/4aw300.png)
Step 1: According to rule \(1\), there is a five-membered carbon chain; hence, the root word is ‘Pent’.
Step 2: According to rule \(2\), there is a substituent. So, the carbon chain is numbered from the left end, which is closest to the substituent.
![4b.png](https://resources.cdn.yaclass.in/9125811d-160e-4a92-97de-375566efdbfb/4bw300.png)
Step 3: All are single bonds between the carbon atoms, and thus the suffix is ‘ane’.
Step 4: According to rule \(6\), the substituent is a methyl group compound located at the second carbon atom.
So, its locant number is \(2\). Thus, the prefix is ‘\(2-Methyl\)’.
Hence, the name of the given compound is \(\text{2-Methyl + pent + ane = 2-Methyl pentane}\).
3. ![5a.png](https://resources.cdn.yaclass.in/a042f4b5-fd68-48ea-b715-bed9fcf15bfd/5aw300.png)
![5a.png](https://resources.cdn.yaclass.in/a042f4b5-fd68-48ea-b715-bed9fcf15bfd/5aw300.png)
Step 1: According to rule \(1\), there is a seven-membered carbon chain; hence, the root word is ‘Hept’. Step 2: According to rule \(2\), there is a substituent. So, the carbon chain is numbered from the left end, which is closest to the substituent.
![5b.png](https://resources.cdn.yaclass.in/5949e73f-af01-48b5-87bf-aeaa31d4a924/5bw300.png)
The correct way of numbering the carbon atoms
![5c.png](https://resources.cdn.yaclass.in/e1fadf51-6526-43db-a353-a95895e708e7/5cw300.png)
The incorrect way of numbering the carbon atoms
Step 3: All are single bonds between the carbon atoms, and thus the suffix is ‘ane’.
Step 4: According to rule \(6\), the substituent is a methyl group compound located at the third carbon atom.
So, its locant number is \(3\). Thus, the prefix is ‘\(3-Methyl\)’.
Hence, the name of the given compound is \(\text{3-Methyl + hept + ane = 3-Methyl heptane}\).
4. ![6aa.PNG](https://resources.cdn.yaclass.in/8e7ac2ff-7135-428a-a5b8-fe98419c55ec/6aaw300.png)
![6aa.PNG](https://resources.cdn.yaclass.in/8e7ac2ff-7135-428a-a5b8-fe98419c55ec/6aaw300.png)
Step 1: According to rule \(1\), there is a five-membered carbon chain; hence, the root word is ‘Pent’.
Step 2: According to rule \(2\), there is a carbon to carbon double bond (\(C=C\)), and thus the suffix is ‘ene’.
Step 3: According to rule \(3\), the carbon chain is numbered from the end of the double bond that has the lowest locant number, as shown below
![6bbb.PNG](https://resources.cdn.yaclass.in/7df80b43-a6ed-43cd-8da0-282c53b10981/6bbbw300.png)
Numbering starts from the double bond.
Step 4: The locant number is \(1\) for the double bond, and hence the suffix is ‘\(-1-ene\)’.
Hence, the name of the given compound is \(\text{Pent + (-1-ene) = Pent-1-ene}\).
These are some of the examples for naming the hydrocarbons according to the IUPAC rule. In the next section, we will see the IUPAC naming for various other compounds.