The pH of a solution is 12. Number of H+ ions present in 1 ml of this solution at 250C is

[H+] = 10-12nH+ present in 1 ml of solution = 10-12 x 1 x 10-3                                                       = 10-15Number of H+ ions present in 1 ml of solution                                                    = 10-15 x 6.023 x 1023                                                   = 6.023 x 108