0.037 g of an alcohol, ROH was added to `CH_3MgI` and the gas evolved measured `11.2 cm^3` at S.T.P. What is the molecular weight of ROH? On dehydration, ROH gives an alkene which on ozonolysis gives acetone as one of the products. ROH on oxidation easily gives an acid containing the same number of carbon atoms. Give structures of ROH and the acid with proper reasoning.

Explanation

`11.2 cm^3 " of " CH_4` is evolved from `ROH = 0.037 g`
`22400 cm^3" of " CH_4` is evolved from ROH
` = 0.037 xx 22400//11.2 = 74 g = 1` mol of ROH.
`:.` Mol. Wt of ROH = `74 + R + 16 + 1`
`:. R = 57 = C_4H_9` or Mol. Formula of ROH is `C_4H_9OH`. Structure of ROH. (i) Since the oxidation of alcohol gives an acid containing the same number of C - atoms, the alcohol must have primary alcoholic group `(-CH_2OH)`. (ii) On dehydration, alcohol gives and alkene which on ozonolysis gives acetone as one of the products. This indicates that the presence of `(CH_3)_2 C `= group in alkene and hence `(CH_3)_2 CH - `group in alchohol.
`:.` Structure of alcohol should be

Oxidation and dehydration of alcohol can be respresented as follows :