Rules for Naming Hydrocarbons in Organic Chemistry
Introduction
- Organic chemistry consists of various compounds that are often difficult to remember by name.
- The video explains the basic rules for naming carbon compounds.
Naming Format
- Like human names, the name of compounds also follows a format: Prefix, Root Word, Suffix.
Root Word
- It depends on the number of carbon atoms present in the longest chain.
- Examples:
- 4 carbons: But
- 3 carbons: Prop
- It's important to remember this chart.
Prefix and Suffix
- Prefix: Comes before the root word.
- Suffix: Comes after the root word.
- Functional groups are divided into low and high priority.
- Use low priority in prefix and high priority in suffix.
Naming Rules
Rule 1: Identify the Longest Carbon Chain
- First, identify the longest carbon chain for naming.
- Examples:
- 5 carbons: Root word = Pent
- 3 carbons: Root word = Prop
Rule 2: Number the Carbon Atoms
- Number the chain in an order with the lowest possible numbers.
- Examples:
- Numbering from Left: Correct
- Numbering from Right: Incorrect
- Correct name: 1-bromo-pentane-3-ol
Rule 3: Write the Name with Appropriate Prefix and Suffix
- Write prefix and suffix with their positions in the numbering.
- Examples:
- 1-bromo-pentane-3-ol
- Primary Suffix: Single bond = ane
- Secondary Suffix: Position of functional group
Examples
-
Described Compound: 2 carbons
- Root word: Eth
- Prefix: 1-bromo
- Final name: 1-bromo-ethane
-
Second Compound: 4 carbons, Double bond
- Root word: But
- Primary Suffix: in
- Final name: But-2-ene
-
Final Compound: 4 carbons, Functional groups (Chlorine, Aldehyde)
- Root word: But
- Prefix: 2-chloro
- Final name: 2-chloro-butanal
Important Tips
- IUPAC naming is a vast topic, this is enough for Class 9 and 10.
- Take screenshots to remember as notes.
- Keep the video and notes safe; they will work as foundation in Class 11 and 12.
- More complex compound names will be learned later.
Share your questions or doubts in the comment section.