A 0.0900 g sample of household bleach is completely reacted with KI(s). The resulting solution is then titrated with 0.150 M NaS2O3 solution. 0.750 mL of the solution is required to reach the colorless endpoint. What is the mass percent of NaOCl (MM = 74.44 g/mole) in the bleach?

9.305%

Explanation:

First, let us consider the balanced equation between the two compounds involved in titration:

1 mole of each of NaClO and is required for complete neutralization.

mole of = molarity x volume

                              = 0.150 x 0.00075

                                 = 0.0001125‬ mole

0.0001125 mole‬ of 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%.

radioactive decay occurs in unstable atomic nuclei – that is, ones that don't have enough binding energy to hold

the nucleus together due to an excess of either protons or neutrons.

the answer is b & c i believe : )