Drawing and naming the carboxylic acids

3 marks · Easy

This question is about drawing carboxylic acids.

(a)

State the number of carbon atoms in methanoic acid.

[1 mark]

(b)

Draw the displayed formula for ethanoic acid.

[2 marks]

Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.

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(a) 1 · must show one carbon atom

(b) — · must show two carbons, COOH group drawn with all bonds, correct H atoms

Common mistakes: leaving out COOH carbon; incorrect bonds in COOH group

Show mark scheme and worked solution

Marking points

B1 (a) · 1 mark · State 1 carbon for methanoic acid (must include COOH carbon).

B2 (b) · 1 mark · Correct carbon backbone with two carbons.

B3 (b) · 1 mark · Fully correct displayed formula: all bonds for –COOH group; all hydrogens shown.

Worked solution

(a) Methanoic acid has 1 carbon atom, as the COOH group includes the carbon and is the only carbon present.

(b) The displayed formula for ethanoic acid:

With all bonds shown:

H O

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H - C - C - O - H