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)
