alleryStart learning →A laboratory needs 250 mL of 2.00 M HCl. How many millilitres of 11.9 M HCl must be diluted to prepare it?
A420 mL
B42.0 mL
C4.20 mL
D1490 mL
Answer & Solution
Correct answer: B. 42.0 mL
1. Dilution keeps the amount of solute fixed, so C1V1 = C2V2.
2. Solve for the stock volume: V1 = C2V2 / C1 = 2.00 M x 250 mL / 11.9 M.
3. The result is 42.0 mL of the concentrated acid.
4. Sanity check: the stock is about six times stronger, so about a sixth of 250 mL is needed.
5. The value 1490 mL swaps the two concentrations in the formula, which would be a further dilution, not a preparation.
_Source: OpenStax Chemistry (CC BY 4.0), Ch 3 "Composition of Substances and Solutions", section 3.3 Molarity_
Keep practising Composition of Substances and Solutions
Browse all Composition of Substances and Solutions questions for AP Chemistry, or explore more Chemistry topics.
Related questions
Rebuild the formula huntPick the heavier moleCrunch the mole numbersIn ammonia, NH3, the three hydrogen atoms together weigh 3.024 amu and the formula mass isWhat is the mass of 0.600 mol of ozone molecules, O3? Use O = 16.00 g/mol.Aspirin is C9H8O4 with a molar mass of 180.159 g/mol. Using H = 1.008 g/mol, what is its mThe EPA maximum safe level of fluoride ion in tap water is 4 ppm. At that level, what massLiquid bleach is 7.4% sodium hypochlorite by mass. What mass of NaOCl is in a 250.0 g bott