10 g of a mixture of BaO and CaO requires `100cm^(3)` of 2.5 M HCl to react completely. The percentage of calcium oxide in the mixture is approximately (Given : molar mass of BaO= 153)

Options

A. 52.6
B. 55.1
C. 44.9
D. 47.4

Answer

A

Explanation

`BaO + 2HCl to BaCl_2 + H_2O`
`CaO + 2HCl to CaCl_2 + H_2O`
2 moles of BaO and CaO require 4 mol of HCl
moles of HCl in `100 cm^3 = (2.5 xx 100)/(1000) = 0.25`mol
4 moles of HCl react with 2 mol of mixture .
0.25 molof HCl react with mixture
` = (2 xx 0.25)/(4) = 0.125` mol
let mass of CaO be .x. g
mass of BaO = (10 - x) g
`(x)/(56) + (10 -x )/(153) = 0.125`
`153 x + 560 - 56x = 0.125 xx 56 xx 153 = 1071`
or ` 97x = 1071 - 560 = 551`
` x = 511/97 = 5.258`
` therefore ` of CaO ` = (5.268)/(10) xx 100 = 52.68%`