Compound $S$ may be obtained from natural compounds. When $S$ is treated with hot, concentrated $\text{KMnO}_4$, the organic product $T$ is formed. Several absorptions in the infra-red spectra of $S$ and $T$ are given. $S$ shows no strong absorption between $1670$ and $1740\,\text{cm}^{-1}$. $T$ shows a strong absorption at $1720\,\text{cm}^{-1}$, but it does not show any strong, broad absorption between $2500$ and $3000\,\text{cm}^{-1}$. On the basis of this information, what might the formulae of $S$ and $T$ be?
Chemistry 9701 · AS & A Level · Analytical techniques