Question

Which of the following is a definition of a base? O a. behaves as a catalyst. O b. accepts H ions from acids. Oc. turns cloudy when dissolved in water O d. donates H ions when dissolved in water O e. releases heat when dissolved in water

Answer 1

Answer: b. accepts $H^+$ ions from acids

Explanation:

According to Arrhenius concept, a base is defined as a substance which donates hydroxide ions $(OH^-)$ when dissolved in water and an acid is defined as a substance which donates hydronium ions $(H_3O^+)$ in water.

According to the Bronsted Lowry conjugate acid-base theory, an acid is defined as a substance which donates $H^+$ ions and a base is defined as a substance which accepts $H^+$ ions.

$NH_3+H_2O\rightarrow NH_4^++OH^-$

Here water is donating $H^+$ ions, and thus act as acid and ammoia $NH_3$ is accepting $H^+$ ions from water and thus is a base.

According to the Lewis concept, an acid is defined as a substance that accepts electron pairs and base is defined as a substance which donates electron pairs.

Thus base is a substance which accepts  $H^+$ ions from acids.