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Answer:
To name CH₃CH₂COOH by IUPAC rules, first identify the longest carbon chain; here, it has three carbons, so the root word is "prop". Second, find the main functional group; COOH means it's a carboxylic acid, so the suffix is "-oic acid." Third, number the chain from the carbon of the functional group; for acids, this is always carbon 1. There are no side chains or double/triple bonds. Combine the root and suffix: "prop" + "oic acid" = propanoic acid. Thus, the compound is named propanoic acid following IUPAC rules.
Answer:
Functional groups decide the chemical properties and naming of organic compounds. They are recognized by unique atoms/groups like –OH, –CHO, –COOH, etc. Each group gets a specific prefix or suffix in IUPAC names. For example, in CH₃CH₂OH (ethanol), –OH is an alcohol, so the name ends with "-ol." In CH₃CHO (ethanal), –CHO is an aldehyde, so the suffix is "-al." Including functional groups ensures every compound's name is unique and clear.
a) CH₃CH₂Cl
b) CH₃CH₂CH₂CH₂OH
Answer:
a) For CH₃CH₂Cl: The longest chain has two carbons (eth-), with chlorine as a substituent (chloro-) at carbon 1. Start numbering from the end nearest to Cl. Thus, it's 1-chloroethane.
b) For CH₃CH₂CH₂CH₂OH: Four carbons (but-), –OH group at carbon 1 (from the end closest to –OH). It's an alcohol ("-ol" suffix). So it's butan-1-ol or 1-butanol.
All naming follows IUPAC rules of lowest number for the functional group.
Answer:
When both a functional group and a double bond are present, numbering starts from the end closest to either the functional group or the double bond, whichever gets the lowest number. The main functional group takes priority if in doubt.
Example: For CH₂=CHCH₂OH, longest chain is three carbons (prop-), one double bond ("-ene"), and an –OH group (alcohol, "-ol"). Numbering from the –OH end: 1 (OH), 2, 3 (double bond after C2). It's prop-2-en-1-ol (or 2-propen-1-ol).
Answer:
Side chains (alkyl groups like methyl or ethyl) are named as prefixes before the root name in IUPAC names. First, identify and number the longest chain. Then, number the chain so the side chains get the lowest numbers. Write the position and name of side chains as prefixes.
Example: CH₃–CH(CH₃)–CH₃ has a 3-carbon main chain (propane) and a methyl group at C-2. It is named 2-methylpropane. Here, "2-methyl" shows a methyl group at the second carbon of propane.
Answer:
The name "2-methylbut-4-ene" is incorrect because "but-4-ene" suggests a double bond at carbon 4, but a four-carbon chain (butane) only has carbons up to 4, so a double bond cannot start at carbon 4. The lowest number for the double bond must be used, and numbering must be from the end nearest the double bond. If the structure is CH₂=CHCH(CH₃)CH₃, the correct name is 3-methylbut-1-ene (double bond starting at C-1, methyl at C-3). Precise numbering and positioning are essential in IUPAC nomenclature.
Answer:
First, find the longest chain including the carboxylic acid (COOH); here, it's 5 carbons (pentanoic acid). Numbering starts from COOH as C-1. Bromine (Br) is on C-2 (counting from COOH end). The correct IUPAC name is 2-bromopentanoic acid.
Answer:
Longest chain: butane. Methyl at C-2, ethyl at C-3. Substituents are named in alphabetical order, not by position: "ethyl" comes before "methyl." Thus, the name is 3-ethyl-2-methylbutane. The numbering is from the end that gives the lowest possible numbers to the substituents. Hence, alphabetical order is key, even if methyl comes at a lower number.
Answer:
The name "1,1-dimethylpropane" suggests two methyl groups on the first carbon of a propane chain. However, this creates a chain longer than three carbons because those methyls would become part of the main chain by IUPAC rules (longest chain). The correct structure is CH₃C(CH₃)₂CH₃, which has a four-carbon chain (butane) with two methyl groups on C-2. The IUPAC name is 2,2-dimethylbutane. Thus, always use the longest chain as the root and place substituents correctly.
Answer:
For CH₃CH=CHCH₂CH₂OH, the longest chain is 5 carbons (pent-). There's a double bond and an –OH group. Number from end closest to double bond or –OH, but since –OH (alcohol) has priority, numbering starts from the –OH end. So, –OH is at C-1; double bond starts at C-3. Hence, the name is pent-3-en-1-ol. Functional group (alcohol) has lower number than the double bond. Both the position of the functional group and the double bond must be indicated in the name.