Question

A nurse used a 0.02-mg/L solution of disinfectant to clean a patient’s wound. What is the concentration of the solution expressed as a percentage?
0.02%
0.2%
2%
20%

Answer 1

Convert mg/L to g/L then to % (g per 100 mL).

0.02 mg/L = 0.00002 g/L.
Percent (w/v) = g per 100 mL = (g/L) / 10 = 0.00002/10 = 0.000002% = 2.0 × 10^−6%.

None of the listed choices are correct.