Question

What of an acid and a base is determined by how completely they dissociate in water ?

Answer 1

Explanation:

• If an acid is strong in nature then upon dissolving in water it will completely dissociate into ions.

For example, HCl is a strong acid and when we dissolve it in water then it will dissociate into hydrogen ($H^{+}$) and chlorine ($Cl^{-}$) ions.

            $HCl + H_{2}O \rightarrow H^{+} + Cl^{-}$

• And, if an acid is weak in nature then it will partially dissociate into ions.

For example, acetic acid is a weak acid and it will dissociate as follows when dissolved in water.

$CH_{3}COOH + H_{2}O \rightleftharpoons CH_{3}COO^{-} + H^{+}$

• Similarly, if a base is strong in nature then it will completely dissociate into ions.

For example, NaOH is a strong base and when it is added to water it will dissociate as follows.

        $NaOH + H_{2}O \rightarrow Na^{+} + OH^{-}$

• And, when a base is weak in nature then it will partially dissociate upon dissolution in water.

For example, ammonia is a weak base and it will dissociate as follows when added to water.

      $NH_{3} + H_{2}O \rightleftharpoons NH^{+}_{4} + OH^{-}$

Answer 2

The strength of an acid and a base is determined by how completely they dissociate in water.

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Strong acids (like stomach acid) break down or dissociate in water. Weak acids  maintains their protons in water.