Correct Answer: (2) 6.8 - 9.2
Solution:We know, boric acid is very weak acid in nature. Although it doesn't have hydronium, it is considered as acid because in water it attaches with OH and makes B(OH)4 -anion. That's why it is an acid. Now, borax is a sodium salt of boric acid. As boric acid is weak acid so, it makes strong conjugate base. When borax dissolved in water, is hydrolyzed to boric acid and OH -anions, yielding a pH of about greater than 9.