Answer:
248 mL of 5% w/v boric acid solution should be used to obtain the solution needed.
Explanation:
We can calculate the volume of the 5% w/v boric acid solution needed to prepare the buffer solution 1.24% w/v using the following equation:
[tex] C_{i}V_{i} = C_{f}V_{f} [/tex]
Where:
[tex]C_{i}[/tex]: is the concentration of the initial solution = 5% w/v
[tex]C_{f}[/tex]: is the concentration of the final solution = 1.24% w/v
[tex]V_{i}[/tex]: is the volume of the initial solution =?
[tex]V_{f}[/tex]: is the volume of the final solution = 1 L
Hence, the volume of the 5% solution is:
[tex] V_{i} = \frac{C_{f}V_{f}}{C_{i}} = \frac{1.24 \%*1 L}{5 \%} = 0.248 L = 248 mL [/tex]
Therefore, 248 mL of 5% w/v boric acid solution should be used to obtain the solution needed.
I hope it helps you!