# Potassium iodide is added to a solution of lead nitrate....what are...?

## $\text{A. The solid product of reaction?}$ $\text{B. The colour of this product?}$ $\text{C. A stoichiometric equation to represent the reaction?}$ $\text{D. Can the reaction be described as a solubility equilibrium?}$

Jul 1, 2017

I presume you mean potassium iodide, $K I$.....is added to the aqueous lead salt.

#### Explanation:

$A .$ $\text{Lead iodide}$

$B .$ $\text{Lead iodide}$ gives a beautiful, bright yellow precipitate......

$C .$ $P b {\left(N {O}_{3}\right)}_{2} \left(a q\right) + 2 K I \left(a q\right) \rightarrow P b {I}_{2} \left(s\right) \downarrow + 2 K N {O}_{3} \left(a q\right)$

The net ionic equation is........

$P {b}^{2 +} + 2 {I}^{-} \rightarrow P b {I}_{2} \left(s\right) \downarrow$

$D .$ This is a $\text{solubility equilibrium}$, where the salt $P b {I}_{2}$ is highly insoluble. I suppose you could also call it a $\text{metathesis}$ or $\text{partner exchange}$ reaction........but I do not know what your syllabus specifies.....Experimentally, we KNOW that all halides are soluble, EXCEPT for those of $H {g}_{2}^{2 +}$, $P {b}^{2 +}$, and $A {g}^{+}$. In the 1st year curriculum, this must simply be known. 