<span>D the temperature decreases and the pressure increases</span>
In this item, it is assume that we are to express the dissociation of the formula unit given to be FeCl₂ into its ionic components.
As seen in the chemical formula, the unit is composed of iron (Fe) and chlorine (Cl). The dissociation is written as follows;
FeCl₂ --> Fe²⁺ + Cl⁻
This equation is balanced by multiplying the appropriate component with a number that would equate the number of atoms in both sides of the equation.
<em> FeCl₂ --> Fe²⁺ + 2Cl⁻</em>
(A) Al(OH)₃ > Mg(OH)₂ > NaOH
polarity is increasing as the metallic character is increasing . So this order is not correct. NaOH as we all know is completely soluble in water.
(B) BaSO₄> CaSO₄ > MgSO₄
This one is also not correct because here also polarity is increasing so solubility should increase.
(C) CaCO₃> NaHCO₃ > Na₂CO₃
this is als not correct .Na₂CO₃ is more polar is completely soluble in water whereas CaCO₃ is insoluble.
(D) AgCl > AgBr > AgI
In D as we go from AgCl to AgI polarity is decreasing so solubility is decreasing .
Molar mass is 28+32 = 60
So take 3.4 x 10^-7/60 and get about 5.7 x 10^-9