A student investigates the limiting reactant in the reaction Pb(NO3)2 + 2 KI -> PbI2 + 2 KNO3 by mixing constant total volume (50.0 mL) of 0.10 M Pb(NO3)2 and 0.10 M KI in five different ratios (Job's plot) and measuring the dry mass of yellow PbI2 precipitate. Maximum yield occurs at V(Pb)=16.7 mL, V(KI)=33.3 mL.
What does the position of the maximum confirm?
- A
Pb^2+ and I- combine 1:1
- B
PbI2 is soluble
- C
KI is the spectator
- Dcheck_circle
The stoichiometric ratio of Pb^2+ : I- in the precipitate is 1:2
Explanation
A maximum yield at 1:2 mol ratio of Pb^2+ : I- (16.7:33.3 mL of equimolar solutions) is consistent with the formula PbI2.