Answer to Question #225165 in Chemistry for Junior

Question

25.00 mL aliquot of 0.016 M NaCl was titrated with 27.52 mL of 0.18 M

AgNO3. Determine whether a precipitate will form at end point. Ksp AgCl = 1.6

x10-10

 

Answer 1

Solution:

C_initial × V_initial = C_final × V_final

V_final = V(NaCl) + V(AgNO₃) = 25.00 mL + 27.52 mL = 52.52 mL

V_final = 52.52 mL

The concentration of NaCl when the solutions are mixed:

C_final(NaCl) = C_initial(NaCl) × (V_initial / V_final)

C_final(NaCl) = (0.016 M) × (25.00 mL / 52.52 mL) = 0.00762 M

C_final(NaCl) = 0.00762 M

The concentration of AgNO₃ when the solutions are mixed:

C_final(AgNO₃) = C_initial(AgNO₃) × (V_initial / V_final)

C_final(AgNO₃) = (0.18 M) × (27.52 mL / 52.52 mL) = 0.09432 M

C_final(AgNO₃) = 0.09432 M

The concentration of Cl^- when the solutions are mixed:

NaCl → Na⁺ + Cl^-

According to the equation above:

[Cl^-] = C_final(NaCl) = 0.00762 M

The concentration of Ag⁺ when the solutions are mixed:

AgNO₃ → Ag⁺ + NO₃^-

According to the equation above:

[Ag⁺] = C_final(AgNO₃) = 0.09432 M

AgCl(s) → Ag⁺(aq) + Cl^-(aq)

The solubility product expression is as follows:

K_sp = [Ag⁺] × [Cl^-] = 1.6×10^-10

K_sp = 1.6×10^-10

Calculate the ion product:

Q = [Ag⁺] × [Cl^-] = (0.09432) × (0.00762) = 0.0007187 = 7.2×10^-4

Q = 7.2×10^-4

Compare Q with the K_sp.

If Q > K_sp, then AgCl will precipitate, but if Q < K_sp, it will not.

Because Q > K_sp, we predict that AgCl will precipitate when the two solutions are mixed.

Answer: Yes, AgCl will precipitate when the two solutions are mixed