Question

The equilibrium constant for the formation of methyl benzoate from methanol and benzoic acid at 25 celsius is 3.77. Use the equation for the equilibrium constant to calculate the theoretical yield of methyl benzoate for the following condition.

a, with equal initial amount of the reactants. (answer: 66%)

b, with a fivefold excess of methanol. (answer: 94%)

Answer 1

CH3OH+ C6H5COOH--<---> C6H5COOCH3+ H2O is the reaction

1. moles of CH3OH= moles of C6H5COOH

let x= moles of CH3OH decomposed

Assume volume is 1 L

so at equiliberium

Concentratinos : CH3OH = C6H5COOH= (1-x) : C6H5CH3COO = x = H2O

K = [H2O] [C6H5CH3COO]/ [C6H5COOH] [CH3OH] = x²/(1-x)²= 3.77

when solved using excel

x= 0.66, theoretical yield

2. let moles of C6H5COOH= 1 and moles of methanol then =5

at equilibrium   x²/ (1-x)*(5-x)= 3.77

when solved using excel, x= 0.942 yiled =94%