This question is about carboxylic acids.
Compound E is a trans stereoisomer of an unsaturated organic acid with the general formula CnH2n−1COOH\text{C}_n\text{H}_{2n-1}\text{COOH}CnH2n−1COOH.
A student plans to analyse acid E by carrying out a titration.
A student first prepares 250.0 cm3250.0\text{ cm}^3250.0 cm3 of a standard solution of 0.150 mol dm−30.150\text{ mol dm}^{-3}0.150 mol dm−3 NaOH\text{NaOH}NaOH for the titration.
The student is provided with solid NaOH\text{NaOH}NaOH and usual laboratory apparatus and equipment.
Describe how the student would prepare the standard solution, giving full details of quantities, apparatus and method.
The student prepares a 250.0 cm3250.0\text{ cm}^3250.0 cm3 solution containing 3.600 g3.600\text{ g}3.600 g of acid E.
The student titrates 25.0 cm325.0\text{ cm}^325.0 cm3 samples of the solution of E with the prepared 0.150 mol dm−30.150\text{ mol dm}^{-3}0.150 mol dm−3 NaOH(aq)\text{NaOH(aq)}NaOH(aq) in the burette.
1 mol NaOH1\text{ mol NaOH}1 mol NaOH reacts with 1 mol1\text{ mol}1 mol of E.
The mean titre of NaOH(aq)\text{NaOH(aq)}NaOH(aq) is 24.00 cm324.00\text{ cm}^324.00 cm3.
Analyse the titration results to determine two possible structures for the trans stereoisomer of organic acid E.
3 exam-style questions on OCR A A Level Chemistry Practical skills assessed in a written examination, covering Planning, Implementing, Analysis, and Evaluation. Each one has a worked solution and a mark scheme showing where the marks go.