If prescribed 850 mg and the available concentration is 425 mg/5 mL, how many mL must be given?

To determine how many mL must be given when prescribed 850 mg with an available concentration of 425 mg/5 mL, first, we need to understand the relationship between the prescribed dose and the available concentration.

The concentration indicates that there are 425 mg in 5 mL. To find out how much liquid is needed to achieve 850 mg, we start by determining how many mg are in 1 mL. This can be found by dividing the concentration by the volume:

425 mg / 5 mL = 85 mg/mL.

Now that we know there are 85 mg in each mL, we can calculate how many mL would be necessary to get to 850 mg by using the following equation:

850 mg ÷ 85 mg/mL = 10 mL.

This calculation indicates that 10 mL of the solution is needed to achieve the prescribed dose of 850 mg. Thus, the answer is 10 mL, which corresponds with the correct choice provided.