Based on solute-solvent interactions,arrange the following in order of increasing solubility in $n$-octane and explain: Cyclohexane,$KCl$,$CH_3OH$,$CH_3CN$.

(D) $n$-octane is a non-polar solvent. According to the principle of "like dissolves like",non-polar solutes dissolve in non-polar solvents,while polar or ionic solutes have low solubility in non-polar solvents.
The order of increasing polarity of the solutes is: $KCl$ (ionic) $> CH_3OH$ (polar) $> CH_3CN$ (polar) $> Cyclohexane$ (non-polar).
Since $n$-octane is non-polar,the solubility will be highest for the non-polar solute and lowest for the ionic solute.
Therefore,the order of increasing solubility in $n$-octane is: $KCl < CH_3OH < CH_3CN < Cyclohexane$.