More than three million carbon compounds have been discovered in the field of chemistry. The diversity of these compounds is due to the capacity of carbon atoms for bonding with one another as well as with other atoms. Most of the carbon compounds are poor conductors of electricity and have low melting and boiling points.
Read the source and answer the sub-parts that follow.
Generated by claude-sonnet-4-6 · 2026-06-15 06:50 · grounding stimulus
Model Answer
(a) The first two members of the homologous series with functional group –Br (haloalkanes) are:
- CH₃Br (Bromomethane)
- C₂H₅Br (Bromoethane)
(b)
(i) –CHO → Aldehyde group
(ii) >C=O → Ketone (Carbonyl) group
(c) Observation: The pink/purple colour of alkaline KMnO₄ is decolourised.
Role of KMnO₄: It acts as an oxidising agent.
Chemical Equation:
$$\text{CH}_3\text{CH}_2\text{OH} \xrightarrow{\text{Alkaline KMnO}_4, \Delta} \text{CH}_3\text{COOH}$$
Ethanol is oxidised to ethanoic acid (acetic acid).
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Explanation
- (a) The –Br functional group series is called haloalkanes. Just replace –H of alkane with –Br; first member = CH₃Br, second = C₂H₅Br.
- (b) These are standard functional group names from the NCERT table — must be memorised exactly.
- (c) Examiners expect three things: observation (decolourisation), role (oxidising agent), and the balanced/word equation. KMnO₄ oxidises ethanol → ethanoic acid; this is a key reaction in the Carbon chapter.