We’re being asked to determine which of the given solutions a precipitate will form.
For this, we need to compare the reaction quotient (Q) vs. the solubility product constant (Ksp).
Recall that when:
• Q > Ksp: the solution is supersaturated and a precipitate will form. Reactants are favored.
• Q = Ksp: the solution is at equilibrium and no precipitate will form.
• Q < Ksp: the solution is unsaturated and no precipitate will form. Products are favored.
We're going to determine if a precipitate will form using the following steps:
Step 1. Write the Q expression.
Step 2. Determine the new concentrations of the ions in the solution formed.
Step 3. Calculate Q.
Step 4. Compare Q and Ksp.
In which of the following mixtures will a precipitate form? Circle all that apply.
a) 10.0 mL of 0.010 M AgNO 3 and 10.0 mL of 0.10 M Na 2SO4 (Ksp for Ag2SO4 = 1.2 x 10 -5)
b) 1.0 mL of 0.10 M Ca(NO 3)2 and 1.0 L of 0.010 M NaF (K sp for CaF2 = 3.45 × 10 -11)
c) 50.0 mL of 0.0020 M AgNO 3 and 250.0 mL of 0.020 M KBrO 3 (Ksp for AgBrO3 = 1.2 x 10 -11)
A. a) and b)
B. a) and c)
C. b) and c)
D. All of the above
E. None of the above
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What scientific concept do you need to know in order to solve this problem?
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