1M HCl and 2M HCl are mixed in volume ratio of 4 : 1. What is the final molarity of HCl solution ?

To find the final molarity of the HCl solution, we can use the formula for the molarity of a mixture:

M1V1 + M2V2 = MfVf

where:

• M1 and M2 are the molarities of the solutions being mixed,
• V1 and V2 are the volumes of the solutions being mixed,
• Mf is the final molarity of the mixture,
• Vf is the final volume of the mixture.

Given:

• M1 = 1M (molarity of the first solution),
• V1 = 4 parts (volume of the first solution),
• M2 = 2M (molarity of the second solution),
• V2 = 1 part (volume of the second solution).

We want to find Mf. The final volume Vf is the sum of V1 and V2, which is 4 parts + 1 part = 5 parts.

Substituting the given values into the formula, we get:

(1M * 4 parts) + (2M * 1 part) = Mf * 5 parts

Solving for Mf, we get:

Mf = [(1M * 4 parts) + (2M * 1 part)] / 5 parts = 1.2M

So, the final molarity of the HCl solution is 1.2M.