Answer:
9.305%
Explanation:
First, let us consider the balanced equation between the two compounds involved in titration:
[tex]NaClO + NaS_2O_3 --> Na_2S_2O_3 + ClO[/tex]
1 mole of each of NaClO and [tex]NaS_2O_3[/tex] is required for complete neutralization.
mole of [tex]NaS_2O_3[/tex] = molarity x volume
= 0.150 x 0.00075
= 0.0001125 mole
0.0001125 mole of [tex]NaS_2O_3[/tex] will therefore require 0.0001125 mole of NaClO for complete neutralization.
Mass of NaClO = mole x molar mass
= 0.0001125 x 74.44
= 0.0083745 g
Percentage by mass of NaClO in the bleach = 0.0083745/0.0900 x 100
= 9.305%
The percentage by mass of NaClO in the bleach is 9.305%.