What is the pH of a buffer made from 0.350 mol of HBrO (Ka = 2.5 × 10⁻⁹) and 0.140 mol of KBrO in 2.0 L of solution?

Which best describes the present-day universe? opaque, expanding very slowly, stars produce heavy elements transparent, expanding at an accelerated rate, stars produce heavy elements opaque, expanding at an accelerated rate, stars produce only hydrogen and helium transparent, expanding very slowly, stars produce only hydrogen and helium