Victor Meyer suggested a method for determining the types of alcohol i.e. (primary, secondary or tertiary). In this method the sample alcohol is treated with PI 3 to get the iodoalkane which is again treated with AgNO 2 to get the nitroalkane. The nitroalkane is then treated with nitrous acid which is obtained by NaNO 2 and HCl. The resulting solution is treated with KOH and the colour is observed. The red, blue and no colour indicates the primary, secondary and tertiary alcohol respectively.