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The relative molecular mass of an alkanoic acid with the empirical formula of CH\(_2\)O is [...

Chemistry
JAMB 2025

The relative molecular mass of an alkanoic acid with the empirical formula of CH\(_2\)O is

[ H = 1, C = 12, O = 16 ]

  • A. 46
  • B. 88
  • C. 60
  • D. 72
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Correct Answer: Option C
Explanation

An alkanoic acid is a type of saturated carboxylic acid with the general molecular formula C\(_n\)H\(_{2n}\)O\(_2\).

Given: empirical formula is CH\(_2\)O.

Recall, (Empirical formula) x =  Relative molecular mass, since the molecular formula is a whole-number multiple of the empirical formula, (CH\(_2\)O)?, which expands to C\(_x\)H\(_{2x}\)O\(_x\).

Equating the general formula for an alkanoic acid to the derived empirical formula general form, we find x = 2 for the oxygen atoms. Thus, the molecular formula is C\(_2\)H\(_4\)O\(_2\).   i.e    C\(_n\)H\(_{2n}\)O\(_2\)  =  C\(_x\)H\(_{2x}\)O\(_x\)

The relative molecular mass with the empirical formula  CH\(_2\)O can be calculated using the following expression:

Relative Molecular Mass = (2×C) + (4×H) + (2×O)

Substituting the values:

Relative Molecular Mass = (2 x12) + (4 x 1) + (2 x16)

                                         = 60

Relative Molecular Mass=24+4+32Relative Molecular Mass equals 24 plus 4 plus 32

Relative Molecular Mass=24+4+32

There is an explanation video available below.


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Explanation Video

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