OH + HCl CH -C - Cl + H O CH - CH - CH + HCl CH CH + H O anhydrous ZnCl CH - CH - OH + HCl No reaction at room temperature Turbidity appears only on heating anhydrous ZnCl anhydrous ZnCl -methylpropan- -ol propan- -ol ethanol -chloro- -methylpropane (immediate appearance of turbidity) -chloropropane (slow appearance of turbidity) Cl ( b) Victor Meyer’s test: This test is based on the behaviour of the different nitro alkanes formed by the three types of alcohols with nitrous acid and it consists of the following steps. i) Alcohols are converted into alkyl iodide by treating it with I /P ii) Alkyl iodide so formed is then treated with AgNO to form nitro alkanes. ii) Nitro alkanes are finally treated with HNO (mixture of NaNO HCl / ) and the resultant solution is made alkaline with KOH. Result: • Primary alcohol gives red colour • Secondary alcohol gives blue colour.
• No colouration will be observed in case of tertiary alcohol. XII U11-Hydroxy XII U11-Hydroxy - - - - CH OH Ethanol I Iodoethane AgNO CH NO HONO Red Colour P/I alcohol Nitroethane NO NO OK K CH CH HONO P/I AgNO CH NO NO Blue Colour CH I NO alcohol propan- -ol -Iodopropane -nitropropane -nitro- -nitroso propane K HONO AgNO P/I I NO No reaction alcohol -methylpropan- -ol -Iodo- -methylpropane -methyl- -nitropropane (No colouration with KOH) Properties of alcohols Physical properties i. Lower alcohols are colourless liquids and the higher members are waxy solids. ii.
They have higher boiling points than the corresponding other organic compounds such as alkanes, aldehydes, ethers etc., this is due to the presence of intermolecular hydrogen bonding present in alcohols. iii. Among isomeric alcohols primary alcohols have higher boiling point and the tertiary alcohols have lower boiling points. XII U11-Hydroxy XII U11-Hydroxy - - - - iv.
The lower members