Achemist must prepare 200.0 ml of hydrochloric acid solution with a ph of 0.60 at 25 °c. he will do this in three steps: • fill a 200.0 ml volumetric flask about halfway with distilled water. • measure out a small volume of concentrated (6.0m) stock hydrochloric acid solution and add it to the flask. • fill the flask to the mark with distilled water. calculate the volume of concentrated hydrochloric acid that the chemist must measure out in the second step. round your answer to 2 significant digits. ml x 5 ?

In the second step, the chemist must measure 8.3 ml of concentrated acid

Explanation:

The concentration of the final solution can be obtained using the pH value:

pH = -log[H] = 0.60

[H] = 10^(-0.60) = 0.25 M

Then, the final concentration of HCl will be 0.25 M because HCl is a monoprotic acid, which means that HCl only has one hydrolyzable proton. Therefore: [HCl] = [H].

The number of moles of HCl in the final solution will be equal to the number of moles present in the volume taken from the stock solution:

n° of moles in the volume taken from stock solution = n° moles in the final solution.

The number of moles can be calculated as follows:

number of moles = concentration * volume

Then:

Ci * Vi = Cf * Vf

where

Ci = concentration of the stock solution

Vi = volume taken from the stock solution

Cf = concentration of the final solution

Vf = volume of the final solution

Replacing with the data, we can obtain Vi:

6.0 M * Vi = 0.25 M * 200.0 ml

Vi = 8.3 ml

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