Answer is: the equilibrium shifts toward the reactants, to the left side of chemical reaction.
It is because lead(II) nitrate dissociates in water:
Pb(NO₃)₂ → Pb²⁺(aq) + 2NO₃⁻(aq).
According to Le
Chatelier's Principle, the position of equilibrium moves to counteract the
change (more lead cations, common ion), the position of equilibrium will move so that the concentration of
products decrease and concentration of reactants of chemical reaction increase.
