Question

Dilute solutions of acids are commonly prepared by diluting the concentrated commercial stock solutions found in chemistry laboratories. The concentration of stock hydrochloric acid is 12.0 M. If 50.0 mL of the stock solution was used to make 1.50 L of a dilute acid solution, what is the concentration of the dilute acid solution?

a) 6.25 M
b) 0.360 M
c) 0.160 M
d) 0.400 M
e) 0.500 M

Answer 1

To find the concentration of a diluted hydrochloric acid solution from a stock solution with a concentration of 12.0 M, we use the equation M1V1 = M2V2, which upon calculation yields a concentration of 0.400 M for the dilute solution.

Step-by-step explanation:

The student is asking about the dilution of a concentrated hydrochloric acid (HCl) solution to prepare a dilute solution. The stock solution concentration is 12.0 M, and it has been diluted to a final volume of 1.50 L using 50.0 mL of the stock. To solve this, we use the dilution equation M1V1 = M2V2, where:

• M1 is the initial molarity (12.0 M)
• V1 is the volume of the concentrated solution used (50.0 mL or 0.050 L)
• M2 is the final molarity of the diluted solution (the value we're solving for)
• V2 is the final total volume of the diluted solution (1.50 L)

To find M2, rearrange the equation to: M2 = (M1V1) / V2, and then substitute the values: M2 = (12.0 M * 0.050 L) / 1.50 L = 0.400 M. Therefore, the concentration of the dilute acid solution is 0.400 M, which corresponds to answer d).