A certain monoprotic weak acid with Ka = 0.49 can be used in various industrial processes. (a) What is the [H+] for a 0.191 M aqueous solution of this acid and (b) what is its pH? Round the [H+] to three significant figures and the pH to two places past the decimal and do NOT use scientific notation

how would i do this?

............HA --> H^+ + A^-

initial..0.191......0.....0
change......-x.......x.....x
equil....0.191-x....x......x

Ka = (H^+)(A^-)(HA) and solve for (H^+), then convert to pH. I expect you will need to use the quadratic equation but perhaps not.