Question

1L of bleach has a mass of 1,100 grams, 7.25% of the mass of bleach is NaClO, 1 mol of NaClO has a mass of 74.44 grams. What is the molarity (mol/L) of NaClO in the bleach? A.0.097 B.0.93 C. 1.07 D.79.75

Answer 1

C. 1.07 M.

Step-by-step explanation:

Hello,

In this case, we can define the molarity of the bleach as shown below:

`M=(moles_(NaClO))/(V_(solution))`

In such a way, given the mass of bleach in a 1-L solution, we can compute the density:

`\rho = (1100g)/(1L)=1100g/L =1.1 kg/L=1.1g/mL`

In such a way, we can use the previously computed density to compute the volume of the solution, assuming a 100-g solution given the by-mass percent:

`V_(solution)=100g*(1mL)/(1.1g) *(1L)/(1000mL) =0.091L`

Afterwards, using the by-mass percent of bleach we compute the mass:

`m_(NaClO)=100g*0.0725=7.25g`

And the moles:

`n_(NaClO)=7.25g*(1mol)/(74.44g) =0.097mol`

Therefore, the molarity turns out:

`M=(0.097mol)/(0.091L)\\ \\M=1.07M`

Thus, answer is C. 1.07 M.

Regards.