Question

2. a) What is the concentration of chlorine in mg/L of household bleach that contains 6 percent by weight of Cl2. Note the density of water is approximately 1,000 kg/m and specific gravity of Cl2 = 1.41 at 20 °C. b) If you are to use this bleach solution to treat 1,000 L water for disinfection, what is the volume of the bleach solution should you use to obtain a target chlorine concentration 1 mg/L?

Answer 1

2. (a) 6% by weight clg means, 100 g solution contains 6g of Uz. Now density of water is 1000 kg/ min 100c bmg 10, 10°9 : 103. 109 10 cm3 . 107 E 206 mg, 1-2 or, 103 g. 11 so, volume of 100g solection is = 100 g 103 g.L-1 So, 0.1 L of solution contains og of cl » 1 L of solution contains 67 0.1 L

=60 g C2 1 = 60,000 mg az so, concentration = 60000 mg/l. by. Target volume = 1000L Target concentration, = 1 mg IL stock concentration = 60000 mg LL Applying Vinitial & Sinitial - Vfinal & Sjinal ☆ Vinitial = Vainal & Sfinal Sinitial af Vinitial = 1000 L x Img.L1 .60000 mg.L-1 => Vanitial = 0.017 L > Vinitial = 17 m. So, we'll take 17 ml of stock soution.