Question

Predict whether or not a precipitate forms upon mixing 175.0 ml of a 0.0055 mkcl solution with 145.0 ml of a 0.0015 m agno3 solution. identify the precipitate, if any. express your answer as a chemical formula. enter noreaction if no precipitate is formed.

Answer 1

Step 1: Write down the chemical reaction

KCl(aq) + AgNO3(aq) → AgCl(s) + KNO3(aq)

The precipitate that can be expected is AgCl

Step 2: Calculate the moles of KCl and AgNO3

# moles of KCl = V(KCl) * M(KCl)

                        = 0.175 L * 0.0055 moles/L = 9.63*10⁻⁴ moles

# moles of AgNO3 = V(AgNO3) * M(AgNO3)

                        = 0.145 L * 0.0015 moles/L = 2.18*10⁻⁴ moles

Since moles of AgNO3 < KCl, the former is the limiting reagent

Therefore, moles of AgCl formed = 2.18*10⁻⁴ moles

Step 3: Predict if AgCl precipitate will be formed

The solubility product Ksp for AgCl = 1.6 *10⁻¹⁰

i.e.

AgCl(s) ↔ Ag⁺(aq) + Cl⁻(aq)

Ksp = [Ag+][Cl-]

if [Ag+][Cl-] > Ksp then precipitation will occur

Now total volume of the solution = 175 + 145 = 320 ml = 0.320 L

[Ag+] = [Cl-] = 2.18*10⁻⁴ moles/0.320 L = 6.81*10⁻⁴ M

[Ag+][Cl-] = (6.81*10⁻⁴)² = 4.64 *10⁻⁷

Since  [Ag+][Cl-] > Ksp, AgCl precipitate will be formed.