What is the ph of a 2.2 m solution of hclo4?

Since HClO4 is a strong acid it will completely dissociate in solution. 

HClO4 + H2O --> H3O+ + ClO4-

Therefore, your concentration of HClO4 will be equal to your amount of H3O+, the conjugate acid in solution. 

The Ka expression is as follows:

Ka= [H3O+][ClO4-] / [HClO4] 

So you know that -log [H3O+] gets you pH, so just plug in [2.2] as your concentration of H3O+ and your answer should be -.34 pH

I’d have to say no because without oxygen in the water the fish would all be dead. so if you want to fish for dead fish, pick the ponds with the lowest oxygen concentrations.