Determine [OH-] of a solution that is 0.135 M in CO3^2-.

I got 0.00532.

When you post a problem like this please include your work and/or what you used for constants; otherwise we can't get the same answer you obtained. I obtained an answer of 0.005 M using k2 of 5.6E-11 so your answer probably is correct.

To determine the hydroxide ion concentration ([OH-]) of a solution, you need to consider the equilibrium reaction involving hydroxide ions and the given compound.

In this case, carbonate ions (CO3^2-) can react with water to form hydroxide ions (OH-) according to the following equation:

CO3^2- + H2O ⇌ HCO3- + OH-

Using the stoichiometry of the reaction, we can conclude that for every one carbonate ion that reacts, one hydroxide ion is produced. Therefore, the concentration of hydroxide ions is equal to the concentration of carbonate ions.

Given that the solution is 0.135 M in CO3^2-, we can conclude that the concentration of OH- ions is also 0.135 M.

Hence, the correct value for [OH-] of the solution is 0.135 M, not 0.00532 M as you calculated.