In its aqueous solution, 99.9% of a substance dissociates to release hydronium ions. Which of the following is true for the substance? (3 points) a
It is a weak acid.

b
It is a weak base.

c
It is a strong acid.

d
It is a strong base.

Yes, endothermic means it turns cold. and some chemical changes include change of tempature.

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 -