Question

Chlorine Bleach is a solution of sodium hypochlorite in water. It usually comes as 5.25% w/v. If you pour in 100.0 ml in your washing machine bleach holder and your washing machine holds a total volume of 3.0 ft³, determine the new percentage of bleach in the filled washing machine. Assume that the density of the resulting solution will be close to water at 1.0 g/ml.

Answer 1

Since initial concentration is 5.25% w/v; per each 100 ml of solution 5.25 gams of sodium hypochlorite will be present.

100ml bleach solution = 5.25 gms of NaOCl₂
​Volume of washing drum = volumeof total solution = 3.0 ft³

​i.e. 3ft3 solution contains 5.25 gms of NaOCl₂

Since 1 ft = 30.48 cm

​3ft³ = 3* (30.48)³ cm³ or ml

^​​Totalsolution volume = 84950.5 cm³ ​or ml

W/V % = (weight of NaOCl₂ ​/ tota lvolume of solution)* 100% = (5.25/ 84950.5)* 100%

Hence final solution W/V % = 0.00618 % or 6.18 * 10^{-3 ​}​w/v

Since density of the solution is 1 gm/ml for this case W/V% = W/W%