1 markVery Short AnswerSection A

Name the functional group present in each of the following organic compounds : (i) $C_2H_5Cl$ (ii) $C_2H_5OH$

Carbon and its Compounds

Functional Groups in Carbon Compounds

Official Answer

The functional groups present in the given compounds are:

(i) $C_2H_5Cl$ (Chloroethane): Halo group / Chloro group ( $-Cl$ )

(ii) $C_2H_5OH$ (Ethanol): Alcohol group / Hydroxyl group ( $-OH$ )

ChloroHaloAlcoholHydroxyl-Cl-OH

Marking Scheme

1Identification of functional group in $C_2H_5Cl$ as Chloro / Halo group (0.5 marks)
2Identification of functional group in $C_2H_5OH$ as Alcohol / Hydroxyl group (0.5 marks)

Hint

Identify the heteroatom or group of atoms replacing hydrogen in the alkane chain using Table 4.3.

Quick Oral Answer

The functional group in $C_2H_5Cl$ is the chloro group ( $-Cl$ ), and in $C_2H_5OH$ , it is the alcohol group ( $-OH$ ).

Analysis & Explanation

According to Table 4.3 of the NCERT textbook:

Chlorine ( $Cl$ ) acts as a heteroatom replacing a hydrogen atom in a hydrocarbon chain, belonging to the class of compounds called Haloalkanes (specifically, Chloroalkanes). The functional group is represented as $-Cl$ .
Oxygen ( $O$ ) in the form of an $-OH$ group replaces a hydrogen atom to form an Alcohol. The functional group is represented as $-OH$ .

Common Mistakes

1Writing the name of the compound instead of the functional group.
2Confusing the alcohol group ( $-OH$ ) with hydroxide ion ( $OH^-$ ); remember that in organic compounds, it is a covalently bonded hydroxyl group.

Interesting Facts

Chloroethane was historically used as a mild topical anesthetic to numb skin before minor procedures due to its rapid cooling effect upon evaporation.

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Frequently Asked Questions

How many marks does this question carry in CBSE Class 10 Science 2012?

This question carries 1 mark in the CBSE Class 10 Science 2012 examination.

Which chapter does this question come from in Science?

This question is from the chapter "Carbon and its Compounds" in the CBSE Class 10 Science syllabus.

What topic does this question cover in Science?

This question covers the topic "Functional Groups in Carbon Compounds" from CBSE Class 10 Science.

What type of question is this in the CBSE Class 10 Science 2012 paper?

This is a Very Short Answer question from Section A in the CBSE Class 10 Science 2012 paper.