(i) Wolff-Kishner reduction method is used to reduce a carbonyl compound like aldehyde or ketone to a hydrocarbon. The reduction reaction takes place when the carbonyl compound is heated with a mixture of hydrazine and a strong base like potassium hydroxide at a temperature range of $453\mathrm{}\mathrm{K}$ to $473\mathrm{}\mathrm{K}$ in ethylene glycol solvent.(ii) Etard reaction is a reaction in which chromyl chloride oxidises methyl group to a chromium complex which gives benzaldehyde upon hydrolysis.