From Lab Calculate the minimum concentration of hydronium io

From Lab

Calculate the minimum concentration of hydronium ions needed to assure that the sulfide ion concentration not exceed the minimum required to precipitate ZnS from a solution 0.01 M in Zn and saturated with hydrosulfuric acid?Assume there are 20 drops per mL. How does one calculate the number of drops of 6M nitric acid to be added to 3 mL of solution to make the hydronium ion concentration become 0.7 M?

Solution

Minimium 0.02 M concentration of hydronium ions needed.