10,000 mg/L equals what percent concentration?

• A. 0.1%
• B. 0.01%
• C. 1%
• D. 10%

Answer: (C)

Percent concentration by weight per volume expresses how many grams of solute are in 100 mL of solution. Here, 10,000 mg per liter equals 10 g per liter. Since 1 liter is 1000 mL, that’s 10 g per 1000 mL, which simplifies to 1 g per 100 mL. That matches 1% w/v, because 1 g in 100 mL is exactly 1% in this convention.

For context, 0.1% would be 1 g per liter, 0.01% would be 0.1 g per liter, and 10% would be 100 g per liter, none of which match 10 g per liter.