Drawing and naming the carboxylic acids
3 marks · EasyThe table shows the molecular formulae of four carboxylic acids.
| Name | Molecular formula |
|---|---|
| methanoic acid | CH2O2 |
| ethanoic acid | C2H4O2 |
| propanoic acid | C3H6O2 |
| butanoic acid | C4H8O2 |
Which acid in the table has the greatest number of hydrogen atoms?
How many carbon atoms does ethanoic acid have?
Give the name of the acid with formula .
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.
Show answer
(a) butanoic acid · must show refers to hydrogen count
(b) 2
(c) butanoic acid
Common mistakes: mistaking number of hydrogens for another acid; counting wrong carbon count
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · Identifies butanoic acid as having most hydrogens (8).
B2 (b) · 1 mark · States ethanoic acid has 2 carbon atoms.
B3 (c) · 1 mark · Correctly names C4H8O2 as butanoic acid.
Worked solution
(a) Butanoic acid has formula C4H8O2 → 8 hydrogen atoms (the most).
(b) Ethanoic acid’s formula is C2H4O2, so 2 carbon atoms.
(c) C4H8O2 is the formula for butanoic acid.