0.71 g of a sample of bleaching powder `(CaOCl_2)` is dissolved in 100 " mL of " water. 50 " mL of " this solution is titrated with KI solution. The `I_2` so liberated required 10 mL 0.1 M `Na_2S_2O_3` (hypo) solution in acidic medium for complete neutralisation. Calculate the percentage of available `Cl_2` from the sample of bleaching power.

Explanation

To solve the problem step by step, we will follow the given information and apply stoichiometric principles.

### Step 1: Calculate the moles of Na2S2O3 used
Given that 10 mL of 0.1 M Na2S2O3 is used for titration, we can calculate the moles of Na2S2O3.

\[ \text{Moles of Na2S2O3} = \text{Volume (L)} \times \text{Molarity (mol/L)} = 0.010 \, \text{L} \times 0.1 \, \text{mol/L} = 0.001 \, \text{mol} \]
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