Three moles of ethanol are oxidised completely to ethanoic acid by acidified K2Cr2O7 (Cr goes from +6 to +3). The number of moles of K2Cr2O7 required is

JEE Advanced levelSingle correct optionDifficulty 3 of 3ro070

Three moles of ethanol are oxidised completely to ethanoic acid by acidified $K X_{2} Cr X_{2} O X_{7}$ (Cr goes from +6 to +3). The number of moles of $K X_{2} Cr X_{2} O X_{7}$ required is

Each ethanol loses 4 electrons (carbinol carbon

- 1

+ 3

), so 3 mol lose 12 mol of electrons. Each

Cr X_{2} O X_{7} X^{2 -}

accepts

2 \times 3 = 6

electrons. Moles of dichromate

= 12/6 = 2