Question

Primary, secondary and tertiary alcohols are distinguished by:
A. Oxidation method
B. Lucas test
C. Victor Meyer's method
D. All of the above

Answer 1

Hint: The test on the basis of which we can distinguish different functional groups are called as a chemical test and all the mentioned tests are referred to chemical tests, as when we distinguish between two or three organic compounds, they have a tendency to react differently exhibiting different visual clues as they exhibit coloration if a reaction takes place.

Complete answer:
Let us know about the chemical test mentioned one by one:
A. Oxidation method: Primary alcohols on oxidation by a suitable oxidizing agent \[N{a_2}C{r_2}{O_7}\] sodium dichromate produces aldehydes which can be further oxidized to carboxylic acids, whereas the secondary alcohol on oxidation will produce ketones and have no tendency to undergo further oxidation, and tertiary alcohols do not undergo oxidation when \[N{a_2}C{r_2}{O_7}\] is added, hence all three can be distinguished by the Oxidation method.
B. Lucas test: This test distinguishes between the turbidity of the solution. Primary alcohol on reacting with Lucas reagent (which is equimolar $ZnC{l_2}$ and concentrated $HCl$) gives no turbidity, whereas on adding Lucas reagent to secondary alcohols produces turbidity in the solution within $5$ minutes, and the addition of Lucas reagent in tertiary alcohols produces instant turbidity, hence all three alcohols can be distinguished via Lucas test.
C. Victor Mayer’s Test: The given alcohols are initially converted to iodide by adding concentrated $HI$ or red phosphorous, The formed iodide is treated with silver nitrate solution to form a nitroalkane, then the formed nitroalkane is finally treated with nitrous acid ( $NaN{O_2} + {H_2}S{O_4}$ ​) and the different colors distinguishes the alcohols, If a blood-red color is observed then it is a primary alcohol, And if a blue color is observed then it is a secondary alcohol, And if no color is observed it is a tertiary alcohol.

Hence, all three above tests can distinguish the primary, secondary and tertiary alcohols. So, Option D is the correct answer.

Note:
The presence of the carboxylic acids formed from primary alcohols can be detected by the addition of ethanol as it has a tendency to exhibit a fruity smell, and the presence of ketone formed from secondary alcohols can be detected with the help of an iodoform test, in which iodine and sodium hydroxide are added which gives us yellow precipitate as a product.