Why does adding sodium chloride to a saturated solution of lead chloride reduce the solubility of pbvi2?

B) Equilibrium is pushed towards the left in the equation

PbCl2 -> Pb+2 + 2Cl-

Explanation:

We have a saturated solution of PbCl2. It means the maximum amount of PbCl2 is dissolved in the solution. If we add sodium Chloride - NaCl, the solubility will be reduced.

NaCl will dissolve into the solution forming Na+ and Cl- ions. Cl- ions are common for the PbCl2 and NaCl. The effect of increasing Cl- ions due to the NaCl will reduce the solubility of PbCl2.

It means if we add Cl- ions or Pb+2 ions independent from the component apportioning them, the solubility will be reduced for the PbCl2, and the equilibrium will be pushed towards the left in the equation

PbCl2 -> Pb+2   + 2Cl-

Finally, we can conclude that the answer is B) Equilibrium is pushed towards the left in the equation:

PbCl2 -> Pb+2   + 2Cl-

since the atomic number is the number of protons in the nucleus, as we move to the left on the periodic table, the electrostatic pull between the nucleus and the valence electron shell decreases. as we move down a group (vertical column), the valence shell energy level gets further and further from the nucleus.