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Course: Class 10 Chemistry (India) > Unit 4
Lesson 5: Functional groupsFunctional groups
Functional groups are group of atoms or bonds that define the function of the hydrocarbon that they get attached to. Examples: Alcohol, Aldehyde, Ketone, Carboxylic acid, Halogens, Double & Triple covalent bonds.
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Created by Ram Prakash. Created by Ram Prakash.
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Isn't OH hydroxyl? Why are we calling it alcohol? Why the special name?(3 votes)
You're right, OH as a functional group is hydroxyl, and compounds with the hydroxyl group are called alcohol. So hydroxyl will be OH while alcohol would be ROH. I think this correction should be made so you could add it in the "Tips & Thanks" section too!(2 votes)
- At1:12to1:14, how will that molecule give off H+ ions? Its a covalent bond, and hence should not dissociate into ions!(3 votes)
You are correct that carboxylic acids, like many other covalent compounds, are primarily held together by covalent bonds. However, under certain conditions, carboxylic acids can undergo ionization or dissociation in water, leading to the release of ions, including hydrogen ions (H+).
The carboxylic acid functional group (-COOH) contains an acidic hydrogen atom, which is attached to an oxygen atom. In an aqueous solution, water molecules can interact with the acidic hydrogen, resulting in the transfer of a proton (H+) from the carboxylic acid to water. This process is represented by the following equilibrium reaction for a generic carboxylic acid, represented as RCOOH:
RCOOH⇌RCOO- + H+
In this reaction,
RCOO− is the carboxylate ion, and H+ is the hydrogen ion (proton). The equilibrium arrow indicates that the reaction can occur in both directions. The degree of ionization depends on factors such as the concentration of the acid and the specific acid in question.
It's important to note that not all covalent compounds ionize in water, and the extent of ionization can vary depending on the strength of the acid. Strong acids ionize completely in water, while weak acids only partially ionize. Carboxylic acids are generally considered weak acids.(1 vote)
"At8:39, Ram you said COOH means 2 oxygen and 1 hydrogen, then it should not be Carboxylic acid cause it contains 3 oxygen right double bond. It should be in the Aldehyed group right?"(1 vote)
Please check the structure of -COOH. It is a carboxylic acid and carboxylic acids always have 1 carbon, 2 oxygen and 1 hydrogen as the functional group.
Aldehyde group (-CHO) always has 1 carbon, 1 oxygen and 1 hydrogen as the functional group.(4 votes)
- Could the ketone group be at the end of the parent carbon chain too, by having a double bond with the adjacent carbon?(1 vote)
- Yes, it is possible for a ketone group to be located at the end of the parent carbon chain if it is part of a carbon-carbon double bond (alkene) in an unsaturated compound. This is known as a terminal ketone or a ketone at the end of the carbon chain.
The general structure of a terminal ketone can be represented as follows:
R-CHO
In this structure, "R" represents the rest of the carbon chain, and the ketone group (-CO-) is at the terminal (end) position. If the adjacent carbon has a double bond (C=C), the compound is referred to as an unsaturated ketone. The presence of the double bond is denoted by the "-ene" suffix in the IUPAC nomenclature.
For example, if the terminal ketone is part of a compound with a double bond, it might be named using IUPAC nomenclature as an unsaturated ketone, such as:
2-buten-3-one
In this example, the ketone group is at the end of the carbon chain, and there is a double bond in the molecule. The "2-buten" part indicates a four-carbon chain with a double bond at the second carbon, and the "3-one" indicates the ketone group at the third carbon.(1 vote)
- Are all these functional groups univalent?(1 vote)
1:12