IIT JEE , AIEEE Forum - Chemistry , Physical Chemistry - what is the pH of ten to power minus eight M HCl sOLUtion?

Greatdreams

           HCl = H⁺ + Cl^-

           H₂0 = H⁺ + OH^-

initially   c       0       0
finally    c-x     x        x

Total [H⁺] = [H⁺] from H₂0 + [H⁺] FROM HCl
            = (x + 10^ -8 )
[OH^-] = x

[H⁺][OH^-] = 10^-14

(x + 10^-8)(x) = 10^-14

x^2 + 10^-8 x - 10^ -14 = 0

On solving this we get x = 9.51 * 10 ^-8

[H+] total = 10^-8 + 9.51*10^-8

= 10.51 * 10^-8

pH = - log [ H+] = -log [ 10.51 * 10^-8 ]

= 6.978

This was pretty common however hope it helps...

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