[xangelofxdeathx]

Which salt produces the most alkaline solution at a concentration of 0.1 M?

A) KNO₃
B) MgCl₂
C) NH₄Cl
D) NaNO₂

My approach: So assuming they all react with water, I am looking for an alkaline or basic solution on the products side. Thus, I want a strong base in one of the products. Choices (A), (B), and (D), give me KOH, Mg(OH)₂, and NaOH respectively, all of them being strong bases.

Now I am stumped, How do I figure out which one is more basic out of KOH, Mg(OH)₂, and NaOH? (The answer is D)

[Mitch]

I don't think they react with water as much as they tend to dissolve in water.

[Borek]

Hydrolysis is a key word here.

http://www.chembuddy.com/?left=pH-calculation&right=pH-salt-simplified

[xangelofxdeathx]

Yeah, I figured it out.

Basically, by inspection with hydrolysis reactions, we see that the salt in

(A) is made of components of strong acid + strong base, which means a neutral solution
(B) is made of components of strong acid + strong base, which means a neutral solution
(C) is made of components of strong acid + weak base, which means a acidic solution
(D) is made of components of weak acid + strong base, which means a basic solution

Therefore the answer is (D). Thanks