A salt is one of the products of neutralization, consisting of an anion from an acid and a cation from a base. Salts can hydrolyze to form neutral, acidic or basic solutions in water. Which of the following salts would form an acidic aqueous solution: NaNO3, LiCH3COO, or (NH4)2SO4? Explain your answer and describe the H+ ion concentration for the acid and base which make up that salt.
This is NOT in any text book; I presume it isn't recommended as a way to explain the pH of salts in aqueous solution. The concept now uses the strength of the anion/cation but that hasn't been helpful in my teaching career; here is a method that works.
NaNO3 + HOH ==> NaOH + HNO3. Look at the products. NaOH is a strong base; HNO3 is a strong acid. Therefore, the solution is neutral since strong = strong. I can give you the new concept if you wish..
LiC2H3O2 + HOH ==> LiOH + HC2H3O2.
LiOH is a strong base; HC2H3O2 is a weak acid. Therefore the solution will be basic since strong out weighs weak. C2H3O2^-(let's use Ac^- to save typing) is hydrolyzed like this.
Ac^- + HOH ==> HAc + OH^-. Obviously releasing OH^- should make the solution basic.
(NH4)2SO4 + 2HOH ==> 2NH4OH + H2SO4. NH4OH is a weak base. H2SO4 is a strong acid. Strong out weighs weak so the solution will be acid. The other way, the NH4^+ will be hydrolyzed like this.
NH4^+ + H2O ==> NH3 + H3O^-. The release of H3O^+ would obviously make the solution acidic.
It's long but I hope this helps. I got through school remember the outlaw method until I understood enough chemistry to do it right. Take yur pick.
To determine which of the salts would form an acidic aqueous solution, we need to analyze the anions and cations present in each salt.
NaNO3: This salt is composed of the sodium cation (Na+) and the nitrate anion (NO3-). Neither sodium nor nitrate ions have a strong tendency to either release or accept protons (H+). Hence, NaNO3 will not form an acidic solution when dissolved in water.
LiCH3COO: This salt contains the lithium cation (Li+) and the acetate anion (CH3COO-). Acetate is the conjugate base of acetic acid (CH3COOH), which means it has the ability to accept protons and form acetic acid. Therefore, when LiCH3COO is dissolved in water, it will hydrolyze to form acetic acid (CH3COOH), resulting in an acidic aqueous solution.
(NH4)2SO4: This salt is composed of the ammonium cation (NH4+) and the sulfate anion (SO4^2-). Ammonium is the conjugate acid of ammonia (NH3), which means it has the ability to release protons and form ammonium ion. As a result, when (NH4)2SO4 is dissolved in water, it will hydrolyze to form ammonium ions (NH4+) and sulfate ions (SO4^2-). The presence of ammonium ions makes the solution acidic.
To summarize, the salt LiCH3COO would form an acidic aqueous solution because the acetate anion (CH3COO-) can accept protons. The H+ ion concentration in the solution can be attributed to the hydrolysis of the acetate anion. The acid-base equilibrium reaction involved is:
CH3COO- + H2O ⇌ CH3COOH + OH-
As a result, the H+ ion concentration will increase, making the solution acidic. The exact concentration of H+ ions would depend on factors such as the initial concentration of the salt and the extent of hydrolysis.