35.0 mL of stock hydrochloric acid solution is added to a 500 mL volumetric flask. A student adds distilled water up to the line. Using a pH meter and logarithms, he finds the molarity of the new solution to be 0.062 M HCl. What is the molarity of the stock solution?

Molarity of stock HCl solution is 0.89 M

Explanation:

The given problem can be solved using laws of dilution.

According to laws of dilution-    

Where, and are initial and final concentration of a solution

            and are initial and final volume of a solution

Here, , and

So, = = 0.89 M

Hence, molarity of stock HCl solution is 0.89 M

the reaction mixture contains some ammonia, plus a lot of unreacted nitrogen and hydrogen. the mixture is cooled and compressed, causing the ammonia gas to condense into a liquid. the liquefied ammonia is separated and removed. the unreacted nitrogen and hydrogen are then recycled back into the reactor .