A 0.3146-g sample of a mixture of NaCl(s) and KBr(s) was dissolved in water. The resulting solution required 47.40 mL of 0.08765 M AgNO3(aq) to precipitate the Cl–(aq) and Br–(aq) as AgCl(s) and AgBr(s). Calculate the mass percentage of NaCl(s) in the mixture

Answer 1

Two equations in two unknowns to be solved simultaneously.
Let x = mass NaCl
and y = mass KBr
-----------------
equation 1 is x + y = 0.3146

equation 2 is
(x/molar mass NaCl) + (y/molar mass KBr) = 0.04740*0.08765

Solve for x, then
%NaCl = (x/mass mixture)*100 = ?
Post your work if you get stuck.

Answer 2

81.4%