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 rarr BaCl_(2)+H_(2)O`
`CaO+2HCl rarr CaCl_(2)+H_(2)O`
Reactions show that 2 moles of mix. of BaO and CaO requires 4 moles of HCl to react completely.
Hence, no. of moles of HCl `=(2.5xx100)/(1000)=0.25` moles
`{:("Now,",HCl,BaO+CaO,),("Initial","4 moles"," 2 moles",),("Final","0.25 moles"," "?,):}`
No. of moles of mixture of BaO and CaO
`=(0.25xx2)/(4)=0.125` moles
Let the mass of CaO be `x` g and BaO is `(10-x)` g
Then, `(x)/(56)+(10-x)/(153)=0.125` [ Mol. mass f CaO `=56, BaO=153`]
`153x+56(10-x)=0.125xx56xx153`
`153x+560-56x=0.125xx56xx153`
`97x=1071-560`
`97x=511`
`x=5.268`
`:.%` of `CaO=(5.268)/(10)xx100=52.68%`