## Chemistry and Chemical Reactivity (9th Edition)

(a) $Na_2C_2O_4$ is formed by: $Na^+$ (which doesn't affect the pH), and $C_2{O_4}^{2-}$ (which is a base); When we add a base to a solution, its pH is going to increase, because it is getting more basic. (b) Ammonium chloride: $NH_4Cl$: - $N{H_4}^+$ : An acid. - $Cl^-$: Neutral compound. When we add an acid to a solution, its pH is going to decrease, because it is getting more acidic. (c) $NaCl$ is formed by: $Na^+$ (which doesn't affect the pH) and $Cl^-$ (which also doesn't); Therefore, the pH will not change.