The ksp of agi is 8.3× 10–17. you titrate 25.00 ml of 0.08160 m nai with 0.05190 m agno3. calculate pag after the following volumes of agno3 are added: (a) at 35.10 ml (b) at ve (volume at equilibrium) (c) at 47.10 ml

(a) 13.64; (b) 8.04; (c) 2.25

Explanation:

AgI(s) ⇌ Ag⁺(aq) + I⁻(aq)

(a) pAg at 35.10 mL

             AgI(s) ⇌ Ag⁺(aq)      +      I⁻(aq)

I/mol:                 1.822 × 10⁻³     2.040 × 10⁻³

C/mol:              -1.822 × 10⁻³     -1.822 × 10⁻³

E/mol:                       0                0.218 × 10⁻³

We have a saturated solution of AgI containing 0.218 × 10⁻³ mol of excess I⁻.

V = 25.00 mL + 35.10 mL = 60.10 mL

                     AgI(s) ⇌ Ag⁺(aq)    +    I⁻(aq)

E/mol·L⁻¹:                         s       3.57 × 10⁻³ + s

Check for negligibility:

(b) At equilibrium

                AgI(s) ⇌ Ag⁺(aq) + I⁻(aq)

E/mol·L⁻¹:                    s             s

(c) At 47.10 mL

              AgI(s) ⇌ Ag⁺(aq)      +      I⁻(aq)

I/mol:                  2.444 × 10⁻³     2.040 × 10⁻³

C/mol:               -2.040 × 10⁻³    -2.040 × 10⁻³

E/mol:                0.404 × 10⁻³              0

V = 25.00 mL + 47.10 mL = 72.10 mL