Question

Among the solubility rules is the statement that all chlorides are soluble except$H{{g}_{2}}C{{l}_{2}},AgCl,PbC{{l}_{2}}andCuCl$.
Write the expression for the equilibrium constant for the reaction represented by the equation:
$AgCl(s)\rightleftarrows A{{g}^{+}}(aq)+C{{l}^{-}}(aq)$
If K is greater than 1, less than 1, or about equal to 1? Explain your answer
Write the expression for the equilibrium constant for the reaction represented by the equation:
$P{{b}^{2+}}(aq)+2C{{l}^{-}}(aq)\rightleftarrows PbC{{l}_{2}}(s)$
If K is greater than 1, less than 1, or about equal to 1? Explain your answer
(A) 1. $K=[A{{g}^{+}}][C{{l}^{-}}]=1$, 2. $K=1/[P{{b}^{2+}}]{{[C{{l}^{-}}]}^{2}}=1$
(B) 1. $K=[A{{g}^{+}}][C{{l}^{-}}]=1$, 2. $K=1/[P{{b}^{2+}}]{{[C{{l}^{-}}]}^{2}}>1$
(C) 1. $K=[A{{g}^{+}}][C{{l}^{-}}]>1$, 2. $K=1/[P{{b}^{2+}}]{{[C{{l}^{-}}]}^{2}}<1$
(D) 1. $K=[A{{g}^{+}}][C{{l}^{-}}]<1$, 2. $K=1/[P{{b}^{2+}}]{{[C{{l}^{-}}]}^{2}}>1$

Answer 1

There are several possible results when a substance is mixed with a solvent. The solubility rules help us to determine which substances are soluble and to what extent.

Complete step by step solution:
The equilibrium constant of a chemical is usually denoted by K gives the relationship between products and reactants when a chemical reaction reaches equilibrium. Equilibrium can be defined as the ratio of the concentration of the products to the concentration of the reactants each raised to their stoichiometric coefficients. At equilibrium Rate of forwarding direction = Rate of backward reaction.
1.$K=[A{{g}^{+}}][C{{l}^{-}}]<1$ , As in given question $AgCl$is solid i.e. insoluble in nature thus the concentration of ions are much less than 1 M.
2. $K=1/[P{{b}^{2+}}]{{[C{{l}^{-}}]}^{2}}>1$, Because $PbC{{l}_{2}}$is insoluble in nature and formed the solid which will reduce the concentration of ions to a low level.

Thus, we can say that option (D) is correct.

Note: At a particular temperature, the rate constants are constant. The ratio of the rate constant of forwarding reaction to the rate constant of backward reaction should be constant and is called an equilibrium constant denoted by $Keq$.