# Chemistry

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i need help.
Calculate the pH of a 0.24 M CoCl3 solution. The Ka value for Co(H2O)63+ is 1.0 10-5.

how do u do these with like the Cl there?

Responses

Chemistry - DrBob222, Monday, February 16, 2009 at 12:35am
Just ignore the Cl^-.
Co(H2O)6Cl3 ==> Co(H2O)6^+3 + 3Cl^-
Then the hexaaquocobalt(III) ion ionizes as (and I will write this a funny way to help you see it).
Co(H2O)6^+3 ==>Co(H2O)5(H2O)^+3==> Co(H2O)5(OH)^+2 + H^+.
Then you write the Ka expression for that last part and solve for H^+ after doing an ICE chart.

i did wat dr. bob said to do and i got a pH of 1.31

what did i do wrong?

• Chemistry -

Show your work for pH = 1.31 and we will try and find the error. I think the answer is closer to pH = 2.8 or so.

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