Question

Brass is a metallic alloy of copper and zinc. The relative percentages of copper and zinc determine the properties of the brass; resistance to corrosion and malleability, for example, are dependent on the relative amounts of copper and zinc. The percentage of zinc within a sample of brass may be determined using the techniques encountered in this experiment. 1. A 0.3400 g piece of brass is allowed to react with hydrochloric acid at the base of eudiometer. The hydrogen gas generated in the reaction occupies a volume of 48.1 mL and leaves behind a column of acid that is 3.65 cm in height. If barometric pressure is measured to be 0.9978 atm, determine the percentages of copper and zinc assuming the temperature of the solution is 22 °C. Approximately 4 mL of 12 M hydrochloric acid were initially added to the eudiometer. The eudiometer was then filled( 45 mL of deionized water) and placed into a 400-mL beaker containing 300 mL of deionized water. Assuming the total volume of solution was 350 mL, and that the solution was uniformly mixed, what was the dilute concentration of the hydrochloric acid? 2.

Answer 1

2.

Given-

Initial volume of HCl =4 ml of 12 M

Final volume of solution =350 ml

Find out the concentration of dilute HCl=?

Step1

Find out the mass of HCl used in 4ml solution

Molar mass of HCl = 36.46g/ mol

Molarity = no. Of moles of HCl /vol.of solution in liter

Molarity= given mass×1000/molar mass ×vol. Of solution

Molarity= given mass×1000/36.46×4

Given mass of HCl = 1.7500g

Step2. Find out the dilute conc. Of HCl in total solution with the help of molarity formula.

Molarity = given mass ×1000/ molar mass × vol. Of solution

Molarity = 1.75×1000/36.46×350 = 0.13713 M

Answer - dilute conc of HCl solution is 0.13713M