Question

If 65.5 ml of HCl stock solution is used to make 450 ml of a 0.675 M HCl dilution, what is the molarity of the stock solution?

Answer 1

Answer:

The molarity of the stock solution needed is 4.6 M ( the last option is correct)

Explanation:

Step 1: Data given

Volume of stock solution = 65.5 mL

Volume of new solution = 450 mL

Concentration of new solution = 0.675 M

Step 2: Calculate molarity of stock solution

C1*V1 = C2*V2

⇒with C1 = the molarity of the stock solution = TO BE DETERMINED

⇒with V1 = the volume of the stock = 65.5 mL = 0.0655 L

⇒with C2 = the molarity of the new solution HCl = 0.675 M

⇒with v2 = the volume of the  new solution HCl = 0.450 L

C1 * 0.0655 L = 0.675M * 0.450 L

C1 = (0.675*0.450 L) / 0.0655 L

C1 = 4.6 M

The molarity of the stock solution needed is 4.6 M ( the last option is correct)