posted by Ryan .
An aqueous solution that 2.10 M in AgNO3 is slowly added from a buret to an aqueous solution that is 1.20×10^−2 M in Cl- and 0.260 M in I- .
When the second ion begins to precipitate, what is the remaining concentration of the first ion?
You should have typed in the Ksp for AgCl and AgI. The Ksp I look up probably aren't the same as in your text. I will use approximations.
Ksp for AgI = about 10^-17.
Ksp for AgCl = about 10^-10
Therefore, AgI will ppt first. AgCl will ppt second.
What will be the (Ag^+) when AgCl just starts to ppt.
That will be (Ag^+) = Ksp/(Cl^-) = 10^-10/0.012 = ?
Now what will be the (I^-) at this point? That will be (I^-) = Ksp/(Ag^+) just calculated.
Post your work if you still need help.
I got it thanks
But how did you get the (Cl^-)?