New Question

2 parts

Part a

Click anywhere in this card to select it for the tutor.

A student plans to determine the concentration, in mol dm–3, of CH3COOH in a bottle of vinegar. The student will carry out a titration with aqueous barium hydroxide, Ba(OH)2(aq). The student’s method is outlined below.

• Dilute 10.0 cm3 of vinegar from the bottle with distilled water and make the solution up to 250.0 cm3.

• Add the diluted vinegar to the burette.

• Titrate 25.0 cm3 volumes of 0.0450 mol dm–3 Ba(OH)2 with the diluted vinegar.

The mean titre of the diluted vinegar is 25.45 cm3. The reaction in the student’s titration is shown below. 2CH3COOH(aq) + Ba(OH)2(aq) → (CH3COO)2Ba(aq) + 2H2O(l)

Calculate the concentration, in mol dm–3, of CH3COOH in the original bottle of vinegar.

Show your working.

Part a

Click anywhere in this card to select it for the tutor.

Suggest one assumption that the student has made that might mean that their calculated concentration of ethanoic acid in the vinegar is invalid.

Predict, with a reason, how the experimental result would differ from the actual concentration of CH3COOH if the assumption were not correct.