Hsc Chemistry 9 Crack May 2026

She flipped to the data sheet. Ka1 of H₂SO₃ = 1.54 × 10⁻². Ka2 = 1.02 × 10⁻⁷. Kb for HSO₃⁻ = Kw/Ka1 = (1×10⁻¹⁴)/(1.54×10⁻²) = 6.49×10⁻¹³.

Mira looked at the clock. 12:31 AM. She smiled—a small, tired, real smile. Then she closed the 9-pack, placed it on top of her textbook, and went to sleep. hsc chemistry 9 crack

Compare Ka2 (1.02×10⁻⁷) to Kb (6.49×10⁻¹³). Ka2 is much larger . So the HSO₃⁻ acts as a weak acid. The solution is slightly acidic. Of course. The pH at equivalence is below 7. Not neutral. That was the trap. She flipped to the data sheet

The crack in the textbook spine. The crack in her confidence. The crack in Question 9. Kb for HSO₃⁻ = Kw/Ka1 = (1×10⁻¹⁴)/(1

Her eyes snapped open. She grabbed a fresh page.

Step two: Add NaOH. The strong base. They neutralise. But at equivalence? No excess base. Only the conjugate base remains. HSO₃⁻. But wait—HSO₃⁻ is amphiprotic . It can act as an acid or a base. She had forgotten that the first time she tried this question.

That night, she’d thrown her textbook across the room. It hit the wall with a satisfying thwack and fell open to Module 6: Acid/Base Reactions. Page 294. A diagram of a titration curve. The shape of a sigh.