Question

I have 345mL of a 1.5M NaCl solution. If I boil the water until the volume of the solution is 250mL, what will the molarity of the solution be?

Answer 1

Answer: Molarity of final solution = 2.07M

Explanation:

Since the amount or number of moles of the solute (NaCl) is constant for the two solutions, we determine it first.

Molarity = no. of moles of solute / volume of solution in liters

Molarity of initial solution is 1.5M, Volume = 345mL or 0.345L

No. of moles = Molarity * volume

No. of moles = 1.5 * 0.345 = 0.5175 moles.

Volume of final solution = 250Ml or 0.250L,

No. of moles = 1.5 * 0.345 = 0.5175 moles

Molarity of final solution = 0.5175moles / 0.250L

Molarity of final solution = 2.07M