Barium hydroxide is an alkali. It reacts with hydrochloric acid. How does the pH of the hydrochloric acid change as excess aqueous barium hydroxide is added?
- AThe pH decreases from $14$ and becomes constant at $7$.
- BThe pH decreases from $14$ to about $1$.
- CThe pH increases from $1$ and becomes constant at $7$.
- DThe pH increases from $1$ to about $14$.