Question

What is the pH of a solution when 42.5 grams of solid Hydrogen Chloride is dissolved into 350.0 mL of water to make a Hydrochloric Acid solution.

Answer 1

I've been in this business a long long time and I've never seen SOLID HCl.
mols HCl = mols/molar mass = 42.5 g/36.5 = ?
Then M = molarity = ?mols from above/0.350 = ? This assume that the total volume of the solution is 0.350 L; i.e., that the HCl added does not change the volume of the solution.
Then pH = -log(HCl) = ?
Post your work if you get stuck.