Question

Question #d755f

Answer 1

375 mL of water is needed.

Explanation:

Using the dilution formula, calculate first for the amount of 2.0 M NaOH needed to prepare 500 mL of 0.5M NaOH solution:

let:
`C_1`= initial concentration of NaOH solution
`C_2`= final concentration of NaOH solution
`V_1` = volume needed
`V_2` = total volume of resulting solution

So then:

`C_1V_1=C_2V_2`
`V_1=(C_2V_2)/(C_1)`

`V_1=(color(blue)cancel(0.5 M)(500 mL))/color(blue)cancel(2.0 M)`

`V_1= 125` `mL`

Then to calculate for the volume of water needed, subtract the volume of the final solution with the computed volume of 2.0 M NaOH needed:

`V_(water)= 500 mL - 125 mL`
`V_(water)= 375 mL`