Question

find the weight of BACL2 in 250cm³solution if given that after addition of 40.0cm³ of 0.102M AGNO3 solution to 30cm³ of the BACL2 solution, back titration of the excess AGNO3 required 20cm³ of 0.098M NH4CNS solution ​

Answer 1

sample containing only BaCl2

and NaCl

is dissolved in 50 mL

of distilled water. Titrating with 0.07916 M

AgNO3

requires 19.46 mL

to reach the end point. What is the weight percent of BaCl2

in the sample? (Molar mass of BaCl2=208.232 gmol−1

and Molar mass of NaCl=58.4425 gmol−1

)

The way I did it was ;

0.1036g of sample contained 266.6745 Molar mass of BaCl2

and NaCl

i.e. 0.1036g of sample= 266.6745 of substance

x g = 208.232 of BaCl2

only

x g=(0.1036*208.232)/266.6745

=0.08089 g

Where 0.08089 g is the mass of BaCl2

present in the sample.

Weight % = (0.08089/0.1036)*100%

= 78%

I don't know if I'm correct.

what is the correct solution to the assignment please?