Question

15.0 mL of 10.5 M NaCl solution is diluted to a volume of 4.0 L. what is the molarity?

Answer 1

Solution.

$V1 = 15.0 mL = 0.015L;$

$C1 = 10.5 mol/L;$

$V2 = 4.0 L;$

$C2 -?;$

We are given the volume and concentration of a stock solution, V₁ and C₁, and the volume of the resultant diluted solution, V₂. We need to find the concentration of the diluted solution, C₂. We thus rearrange the dilution equation in order to isolate C₂:

$C_1V_1 = C_2V_2; \implies C_2 = (C1V1)/V_2;$

$C2 = (10.5 mol/L\sdot0.015L)/4.0 = 0.0394mol/L;$

Answer: $C_2 = 0.0394M.$