A sample of copper oxide weighing 2.086 g and containing 13.04% CuO is dissolved in acid, the pH adjusted and excess KI is added, liberating I₂.
How many cm' of 0.1046 M Na₂S₂O₃ are required to titrate the I₂?
Note: 2Cu²⁺+ 4I⁻ → 2CuI(s) + I₂
2S₂O₃²⁻ + I₂ → S₄O₆²⁻ + 2I⁻