in naming hydrocarbons ..
if the hydocarbon has a double bond .. do i automatically consider it from the parent chain.. or it could be in a branched part
The longest chain containing the double bond is the parent compound.
if the double bond is not in the longest chain ... ??!!
If it's a double bond C=C (as opposed to a COOH or CHO(aldehyde) or RCOR'(a ketone), the longest chain containing the double bond is the parent. All of the other "longer" chains or parts of them are names as substituents of the parent. Double bonds (C=C double bonds) take precedence over single bonds.
thank you ..
When naming hydrocarbons, the location of double bonds must be specified. A double bond can be present in the parent chain or in a branched part of the hydrocarbon molecule. Here's how you can determine the correct name for a hydrocarbon with a double bond:
1. Determine the longest continuous carbon chain in the hydrocarbon molecule. This chain will serve as the parent chain for naming purposes.
2. Assign a prefix to the parent chain based on the number of carbon atoms it contains. For example, if the parent chain contains three carbon atoms, the prefix would be "prop-".
3. Locate the position of the double bond within the parent chain by assigning a number to each carbon atom in the chain. The double bond should be between two of these numbered carbon atoms.
4. Include the position of the double bond in the name by adding a numerical prefix before the parent chain's prefix. For example, if the double bond is between the second and third carbon atoms in a four-carbon chain, the name would include the prefix "2,3-d".
5. Finally, add the suffix "-ene" to the parent chain's prefix to indicate the presence of a double bond. This suffix replaces the "-ane" suffix used for naming hydrocarbons without double bonds.
If the double bond is not present within the parent chain and is in a branched part of the molecule, you would locate the double bond as described above and include it in the name using the appropriate numerical prefix.
Remember to follow established naming conventions for different types of branched hydrocarbons, such as substituents, and to order the substituents alphabetically when naming them.
It's important to note that for complex hydrocarbons with multiple double bonds or other functional groups, it may be necessary to prioritize and properly name the functional groups.