How many milliliters of concentrated  6.3 M  HCl would be needed  to make 834 milliliters of a final concentration of 2.73M HCl?

To solve this problem, you can use the formula M1V1 = M2V2, where M1 is the initial molarity, V1 is the initial volume, M2 is the final molarity, and V2 is the final volume.

Here, you are asked to find V1, the volume of the concentrated HCl needed. The initial molarity M1 is 6.3M, the final molarity M2 is 2.73M, and the final volume V2 is 834 mL.

Rearranging the formula to solve for V1 gives V1 = M2V2 / M1.

Substituting the given values into the formula gives V1 = (2.73M * 834 mL) / 6.3M.

Performing the calculation gives V1 = 359.7 mL.

Therefore, you would need approximately 359.7 mL of the concentrated 6.3M HCl to make 834 mL of a 2.73M HCl solution.