How can determine the initial molar concentration of i-

Question

1. Determine the initial molar concentration of I^- (at time= 0, before reaction) if 4.0 mL of 0.30 M KI is mixed with 1.0 mL of demonized water, 1.0 mL of buffer solution, 1.0 mL of 0.02 MNa₂S₂O₃, and 3.0 mL of H₂O₂.

2. Determine the numbers of moles of I2 are generated in the reaction during the time lapse of the rate measurement?
a)   2 I^- (aq) +H₂O₂(aq) + 2 H₃O⁺ (aq)→ I₂(aq) + 4 H₂O(l)
b)   2 S₂O₃^2- (aq) +I₂(aq) → 2I^-(aq) +S₄O₆^2-(aq)