`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. 0.321
B. 0.162
C. 0.218
D. 0.11

Answer

A

Explanation

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