Students use a 2.5 M solution of diluted hydrochloric acid. The Molarity of the solution they end up with is 125 M. and had a volume of 5500mL. What volume of the concentrated HCI
did they begin with?

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 -