Oxidation of alcohols by strong oxidants in acid medium

Exercise 6

    

$2.2\;g$ of a primary aliphatic saturated mono-alcohol is treated with an excess of potassium dichromate. The resulting acid is separated and titrated: At equivalence were introduced $25\;mL$ of a $ 1\;M$ sodium hydroxide solution . Deduce the molecular formula of this alcohol!

$n_{carboxylic\;acid}$ $=$ $1\cdot 0.025$ $=$ $0.025$ One mole alcohol gives one mole carboxylic acid. $n_{alcohol}$ $=$ $0.025$ $M_{alcohol}$ $=$ $\frac{2.2}{0.025}$ $=$ $88\frac{g}{mol}$ General formula: $C_nH_{2n+2}O$ $12n$ $ +$ $2n$ $+$ $2$ $+$ $16$ $=$ $88$ $n$ $=$ $5$ Molecular formula: $C_5H_{12}O$