Final answer:
To find the % of available chlorine in the bleaching powder sample, 0.015 moles of available chlorine were calculated using the titration data with hypo. Multiplying the moles by chlorine's molar mass gave the mass of chlorine (1.065 g), and the percentage was subsequently calculated as 15% by dividing the mass of chlorine by the mass of the sample and multiplying by 100.
Step-by-step explanation:
To determine the % of available chlorine in the bleaching powder sample, we'll analyze the interaction between the chlorine in the bleaching powder and potassium iodide (KI) in the presence of acetic acid. The reaction produces iodine (I2), which is then titrated with sodium thiosulfate (hypo). Given that 60 mL of 0.5 N hypo is required for the titration, we can calculate the amount of chlorine present.
Firstly, we need to establish the molarity (M) of the hypo solution. Since normality (N) is equal to molarity times the equivalent factor, which is 2 for sodium thiosulfate (due to the two available electrons per molecule), we have:
M = Normality / 2 = 0.5 N / 2 = 0.25 M
Now, using the stoichiometry of the reaction and the volume of hypo used, we can calculate the number of moles of I2 that reacted:
Number of moles of I2 = Molarity × Volume (in liters) = 0.25 × 0.060 L = 0.015 moles
Since the reaction between chlorine and iodide to produce iodine is 1:1, the moles of available chlorine in the sample are also 0.015. To find the mass of chlorine, we multiply the moles by the molar mass of chlorine (Cl2, approximately 71 g/mol):
Mass of Cl2 = Moles of Cl2 × Molar mass of Cl2 = 0.015 moles × 71 g/mol = 1.065 g
Finally, the percentage of available chlorine in the sample is calculated by dividing the mass of chlorine by the mass of the sample and then multiplying by 100:
% available chlorine = (Mass of Cl2 / Mass of the sample) × 100 = (1.065 g / 7.1 g) × 100 = 15%