Question

Consider the insoluble compound nickel(II) hydroxide , Ni(OH)2 . The nickel ion also forms a complex with cyanide ions . Write a balanced net ionic equation to show why the solubility of Ni(OH)2 (s) increases in the presence of cyanide ions and calculate the equilibrium constant for this reaction. For Ni(CN)42- , Kf = 1.0×1031 . Use the pull-down boxes to specify states such as (aq) or (s).

Answer 1

Answer: Equilibrium constant for this reaction is
`2.8 * 10^(15)`.

Step-by-step explanation:

Chemical reaction equation for the formation of nickel cyanide complex is as follows.

`Ni(OH)_(2)(s) + 4CN^(-)(aq) \rightleftharpoons [Ni(CN)_(4)^(2-)](aq) + 2OH^(-)(aq)`

We know that,

K =
`K_(f) * K_(sp)`

We are given that,
`K_(f) = 1.0 * 10^(31)`

and,
`K_(sp) = 2.8 * 10^(-16)`

Hence, we will calculate the value of K as follows.

K =
`K_(f) * K_(sp)`

K =
`(1.0 * 10^(31)) * (2.8 * 10^(-16))`

=
`2.8 * 10^(15)`

Thus, we can conclude that equilibrium constant for this reaction is
`2.8 * 10^(15)`.