`10 g` of a sample of a mixture of `CaCl_(2)` and `NaCl` is treated to precipitate all the calcium as `CaCO_(3)`. This `CaCO_(3)` is heated to convert all the `Ca` to `CaO` and the final mass of `CaO` is 1.62 g.The percent by mass of `CaCl_(2)` in the origial mixture is

Options

A. `32.1%`
B. `16.2%`
C. `21.8%`
D. `11.0%`

Answer

A

Explanation

`CaCl_(2) + NaCl = 10g`, Let weight of `CaCl_(2) = xg`
`{:(CaCl_(2), rarr ,CaCO_(3) ,rarr ,CaO),("1 mol",,"1 mol",,"1 mol"),((x)/(111) "mol",,(x)/(111)"mol",,(x)/(111)"mol"):}`
Mole of `CaO = (1.62)/(56) :. (x)/(11) = (1.62)/(56) rArr x = 3.21 g , " "% of CaCl_(2) = (3.21)/(10) xx 100 = 32.1 %`