Question

For a given aqueous solution, if [H+]= 1.0 times 10^-3M, what is [OH-]?

Answer 1

Answer: for the given aqueous solution, the [OH-] value is 1.0 x 10^-11 M

Step-by-step explanation:

The question requires us to calculate the concentration of OH- ions ([OH-]) in an aqueous solution, knowing that the concentration of H+ ions ([H+]) is 1.0 x 10^-3 M.

To solve this problem, we can consider the self-ionization of water and its correspondent ionization constant:

`2H_2O_((l))\rightleftarrows H_3O_((aq))^++OH_((aq))^-\text{ K}_w=1.00*10^(-14)`

Note that the constant of equilibrium expression for the reaction above, Kw, can be written as:

`K_w=[H_3O^+\rbrack*[OH^-\rbrack`

Also, note that H3O+ ions are equivalent to H+ ions.

Therefore, we can rearrange the equation above to calculate the concentration of OH- ions in an aqueous solution, knowing that the equilibrium constant for the self ionization of water is 1.00 x 10^-14 and that the concentration of H+ ions in the solution is 1.0 x 10^-3:

`\begin{gathered} K_w=[H_3O^+\rbrack*[OH^-\rbrack\rightarrow[OH^-\rbrack=(K_w)/([H_3O^+\rbrack) \\ \\ [OH^-\rbrack=(1.00*10^(-14))/(1.0*10^(-3))=1.0*10^(-11)M \end{gathered}`

Therefore, for the given aqueous solution, the [OH-] value is 1.0 x 10^-11 M.