Q.An aqueous solution of borax is

1. Composition of borax. Borax, $\text{Na}_2\text{B}_4\text{O}_7\cdot 10\text{H}_2\text{O}$, can be thought of as the salt formed from sodium hydroxide (a strong base) and boric acid (a weak, monobasic acid).
2. Hydrolysis in water. When dissolved in water, borax hydrolyses:

3. Why the solution is basic. Since the base produced (NaOH) is strong and fully dissociates, while the acid produced (H$_3$BO$_3$) is weak and only partially ionises, the solution contains an excess of free hydroxide ions relative to the acid's ionisation, making the overall solution alkaline (basic) to litmus. …

Write borax's hydrolysis equation, identify the strength of the base and acid produced (strong base, weak acid), and conclude the solution must be bas …

• Confusing "amphoteric" (a substance able to react as both acid and base) with the pH character of a solution — borax's solution is simply basic, not amphoteric. …