Convert an alcohol into a ketone by heating it in reflux apparatus with potassium dichromate/K2Cr2O7 and dilute sulfuric acid/H2SO4 (this is an oxidation reaction).Then convert ketone into hydroxynitrile by adding acidified potassium cyanide/KCN(aq) or HCN(g) at 25oC (this is nucleophilic addition)