The enthalpies of neutralization of a weak base AOH and a strong base BOH by HCl are -12250 cal/mol and -13000 cal/mol respectively. When one mole of HCl is added to a solution containing 1 mole of AOH and 1 mole of BOH, the enthalpy change was -12500 cal/mol. In what ratio is the acid distribution between AOH and BOH?

Options

A. `2 : 1`
B. `2 :3`
C. `1 :2`
D. None of these

Answer

A

Explanation

`underset(1 mol)(AOH) + underset(x mol)(HCl) rarr ACl + H_2O , Delta H = -12250 cal = -12250 x cal`
`underset(1 mol)(BOH)+underset(x mol)(HCl) rarr BCl + H_2O , Delta H = -13000 cal = -13000 (1 - x) cal`
`12500 = 12250 x + 13000 (1 - x)`
`12500 = 12250 x + 13000(1 + x)`
`12500 = 12250 x + 13000 - 13000 x`
`x = 0.67`
`x/(1 - x) = (0.67)/(0.33) = 2 : 1`