Deduce the empirical formula of vitamin C.
The vitamin C concentration is determined by titration with $I_2(aq)$. A vitamin C tablet is dissolved in water to make $200\ \text{cm}^3$ of vitamin C solution. A $5.00\ \text{cm}^3$ portion of this solution is placed in a flask with about $150\ \text{cm}^3$ of water and an indicator. Precisely $28.40\ \text{cm}^3$ of $5.00 \times 10^{-4}\ \text{mol dm}^{-3}\ I_2(aq)$ reacts with the vitamin C sample in the flask. $[M_r: \text{vitamin C},\ 176]$.
Calculate the amount, in mol, of $I_2(aq)$ added to the flask in this titration.
Use your answer to (b)(i) to work out the mass, in g, of vitamin C in the tablet. Show your working. (If you were unable to calculate a value for the amount of $I_2(aq)$ in (b)(i), use the value $2.64 \times 10^{-4}\ \text{mol}$. This is not the correct value.)
Deduce the role of $I_2(aq)$ in the reaction in Fig. 4.2.
Suggest two reasons why hot concentrated acidified potassium manganate(VII) is not a suitable reagent for making Q from vitamin C.
Predict two absorptions that will appear in the infrared spectra of both vitamin C and Q. Describe the relevant bond and the specific functional group responsible for each absorption you identify.