Drawing and naming the alcohols

2 marks · Easy

The displayed formula of an alcohol shows four carbon atoms in a straight chain, with the –OH group attached to the terminal (end) carbon.

Calculate the total number of hydrogen atoms in one molecule of this alcohol. Give your answer using IUPAC naming if possible.

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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10; butan-1-ol

Must show: hydrogen count = 10, IUPAC name: butan-1-ol

Common mistakes: 8; 9; incorrect position of –OH group

Show mark scheme and worked solution

Marking points

M1 · 1 mark · Identifies the molecule as butan-1-ol and/or recognises the structure (CH3CH2CH2CH2OH or butan-1-ol).

A1 · 1 mark · Correctly calculates 10 hydrogen atoms.

Worked solution

The alcohol with four carbons in a straight chain and –OH on the end is butan-1-ol (CH3CH2CH2CH2OH).

Counting hydrogens: CH3 (3 H) + CH2 (2 H) + CH2 (2 H) + CH2 (2 H at end before OH) + OH (1 H):

So there are 10 hydrogen atoms in one molecule of butan-1-ol.