Question

85.
2.34 gram of'impure sodium chloride is treated
with excess of AgNO, solution then 2.87 g of
silver chloride (Mw = 143.5) precipitate is formed.
What is the percentage purity of sodium chloride?
(1) 50 (2) 100 (3) 40 (4) 70
Equivalent weight of FeS, (Molar mass = M) in
the half reaction Fes, Fe,O, + SO, is :-
86.
(1) M
(2)
6
(4)​

Answer 1

Percentage purity of sodium chloride =50%

Explanation:

• $NaCl+AgNO_3 \to AgCl+NaNO_3$

         23+35.5=           108+35.5=      

           58.5                        143.5

            ?                            =2.87 g

• 143.5 g of $AgCl$ is obtained from 58.5 g of pure $NaCl$

• 2.87 g of  $AgCl$ is obtained from pure $NaCl$ =

                  $\frac{58.5}{143.5} \times 2.87 = 1.17 g$

• According to the given data, 2.34 g of impure sodium chloride contain pure $NaCl$ =1.17 g

• Then 100 g of $NaCl$ contain pure $NaCl$ $=\frac{1.17}{2.34} \times 100$ = 50 g

• Percentage purity of sodium chloride =50%