Coconut oil contains a triester with three identical R groups - AQA - A-Level Chemistry - Question 1 - 2021 - Paper 2

The type of compound shown by the formula RCOOK is a potassium carboxylate salt or simply a carboxylate salt. One use for carboxylate salts includes their function as surfactants in soaps and detergents.

Given that the molecular mass M = 638.0, we first subtract the mass of the carboxylate fragments: 638 - 173 = 465 g/mol. The aliphatic chain contributes $14n$ to the molecular mass, thus we solve for n: $465 = 14n$ Substituting gives: n = \frac{465}{14} = 33.21428571
Since n must be an integer, round down to 33.

First, we determine the amount of HCl reacted: $\text{Amount of HCl} = C_{HCl} \times V_{HCl} = 0.100 \text{ mol dm}^{-3} \times 15.65 \text{ cm}^3 \times \frac{1}{1000} = 0.0015655 \text{ mol}$ The remaining KOH: \text{Moles of KOH initially} = \frac{0.421}{56.1} \approx 0.00749 \text{ mol} \text{Moles of KOH after reaction} = 0.00749 - 0.0015655 = 0.0059245
The amount of triester = $\text{moles of KOH that reacted} \times \frac{M}{3}$ = $(0.0015655) * \frac{638}{3}$
Now, we calculate the percentage: $\text{Percentage} = \left( \frac{\text{mass of triester}}{1.450} \right) \times 100$ The final percentage should be calculated as required.

Aqueous ethanol acts as a suitable solvent because it dissolves both the coconut oil (triester) and KOH, thus facilitating the hydrolysis reaction between them efficiently.

A proper safety precaution is to wear safety goggles.

Justification: This ensures that if any solution splashes or spills during heating, it does not harm the eyes.