[Antonio8]

A solid 0.5330-g sample which contains only AgNO3(s) and Hg2(NO3)2(s) is dissolved in aqueous medium and the metal cations are precipitated as a mixture of the respective insoluble cobalticyanide salts.
3Ag+(aq) + Co(CN)63−(aq) → Ag3[Co(CN)6](s)
3Hg22+(aq) + 2Co(CN)63−(aq) → (Hg2)3[Co(CN)6]2(s)
The washed and dried precipitate has mass 0.5571 g.
What was the wt% of AgNO3 in the original sample?


I tried to solve this using (weight precipitate)*(gravimetric factor)(100) / weight of sample but i got the wrong answer!? can someone please shed some light on this for me !?

[Pradeep]

Take number of moles of AgNo3 as X, and Hg2(No3) 2 as Y. Then multiply by their molar waits.

X * M1 + Y * M2 = 0.5330

And

X/3 * M 3 + Y/ M 4 = 0.5571

The solve two simultaneous equations. ( You can calculate M1, M2, M3, M4 by using respective atomic weights)

Can you understand the calculation?