Answer:
Option C. Ksp for PbCl₂
Explanation:
The equilibrium constant that is established between a solid and its ions in a saturated solution is what is known as Ksp (solubility product). It is an equilibrium constant based on concentrations.
The concentrations must be equilibrium, that is, concentrations of the ions in a saturated solution. To be sure of such saturation it is convenient to form a precipitate.
The smaller the Kps, the more insoluble the salt
Explanation:
The given reaction equation will be as follows.
![[FeSCN^{2+}] \rightleftharpoons [Fe^{3+}] + [SCN^{-}]](https://tex.z-dn.net/?f=%5BFeSCN%5E%7B2%2B%7D%5D%20%5Crightleftharpoons%20%5BFe%5E%7B3%2B%7D%5D%20%2B%20%5BSCN%5E%7B-%7D%5D)
Let is assume that at equilibrium the concentrations of given species are as follows.
M
M
M
Now, first calculate the value of
as follows.
![K_{eq} = \frac{[Fe^{3+}][SCN^{-}]}{[FeSCN^{2+}]}](https://tex.z-dn.net/?f=K_%7Beq%7D%20%3D%20%5Cfrac%7B%5BFe%5E%7B3%2B%7D%5D%5BSCN%5E%7B-%7D%5D%7D%7B%5BFeSCN%5E%7B2%2B%7D%5D%7D)
= 
= 
Now, according to the concentration values at the re-established equilibrium the value for
will be calculated as follows.
![K_{eq} = \frac{[Fe^{3+}][SCN^{-}]}{[FeSCN^{2+}]}](https://tex.z-dn.net/?f=K_%7Beq%7D%20%3D%20%5Cfrac%7B%5BFe%5E%7B3%2B%7D%5D%5BSCN%5E%7B-%7D%5D%7D%7B%5BFeSCN%5E%7B2%2B%7D%5D%7D)
M
Thus, we can conclude that the concentration of
in the new equilibrium mixture is
M.
The temperature at which the process be spontaneous is calculated as follows
delta G = delta H -T delta S
let delta G be =0
therefore delta H- T delta s =0
therefore T= delta H/ delta S
convert 31 Kj to J = 31 x1000= 31000 j/mol
T=31000j/mol /93 j/mol.k =333.33K