What does the host mean when he says that the acid has “donated a proton” to the water? A.

When hydrochloric acid is dissolved in water, a proton disappears in the chemical reaction.

B.

When hydrochloric acid dissociates, a positive hydrogen atom is accepted by water to form H₃O+.

C.

When hydrochloric acid dissociates, a negative hydrogen atom is accepted by water to form H₃O-.

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 lechatelier's principle, the position of equilibrium moves to counteract thechange (more lead cations, common ion), the position of equilibrium will move so that the concentration ofproducts decrease and concentration of reactants of chemical reaction increase.read more on -