Question

4. Each time that you prepare a diluted bleach solution you will want it to have a [OH-] = 0.02. Calculate how much 1.00 M NaOH you need to add to d.1. water to get every 20 mL of this concentration of OH- ion. Express your answer in drops of 1.00 M NaOH. (Assume that there are 20 drops in 1 m.)

Answer 1

8 drops of 1.00 M NaOH will be needed.

Step-by-step explanation:

Concentration of
`[OH^-]` in bleach solution = 0.02 M

`NaOH\rightarrow OH^-+Na^+`

`NaOH=[OH^-]=0.02M`

Concentration of bleach solution we want ,
`M_1` = 0.02 M

Volume of the bleach solution,
`V_1` = 20 ml

Concentration of NaOH solution,
`M_2` = 1.00 M

Volume of the NaOH solution required ,
`V_2` = ?

`M_1V_1=M_2V_2`

`0.02 M* 20 mL=1.00 M* V_2`

`V_2=(0.02 M* 20 mL)/(1.00 M)=0.4 mL`

1 mL = 20 drops

0.4 mL = 0.4 × 20 drops = 8 drops

8 drops of 1.00 M NaOH will be needed.