For this problem, we’re being asked to calculate the concentration of I- in a solution obtained by shaking 0.16 M KI in excess AgCl.
AgCl and AgI dissociates into ions in a solution:
AgCl ⇌ Ag+(aq) + Cl–(aq) → Ksp = 1.8 x 10-10
AgI(s ⇌ )Ag+(aq) +I–(aq) → Ksp = 8.5 x 10-17
**Ksp values can be found in textbooks/online
Recall that the higher the Ksp, the more soluble the compound: AgCl is more soluble than AgI → so AgI will precipitate first
We can write the reaction between 0.16 M KI and excess AgCl:
KI + AgCl → KCl + AgI
** one mole of KI produces 1 mole of AgI → 0.16 M of KI gets converted to AgI (assuming no volume change)
Calculate the concentration of I- in a solution obtained by shaking 0.16 M KI with an excess of AgCl(s).
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What scientific concept do you need to know in order to solve this problem?
Our tutors have indicated that to solve this problem you will need to apply the Selective Precipitation concept. If you need more Selective Precipitation practice, you can also practice Selective Precipitation practice problems.