Question

1 A) Which of the following pairs of solutions when mixed will form a buffer solution? Group of answer choices H2SO4 and Ca(OH)2 NH3 and NH4Br NaNO3 and HNO3 KOH and KNO2

B)Phosphoric acid, H₃PO₄, is a triprotic acid with the following K_a values:

K_a1 = 7.5 x 10^-3; K_a2 = 6.2 x 10^-8; K_a3 = 3.6 x 10^-13

In a solution of 0.15 M H₃PO₄, which species will be most abundant?

H₃O⁺

H₃PO₄

HPO₄^2-

H₂PO₄^-

Answer 1

- Buffen solution is made by mixing weak and with its salt on weak base with its salt Therefore NH3 and NHA BD form buffer solution because se Nhzis a weak base of ammonia (NH₂). NH Bn is a salt => H₂P04 (phosphoric acid) dissociation of this acid shown below H₂POg Hapoy+HI Kal = 7.5*10 3 Hapo HPORT & Po? +HT & poß-+H7 Kag= 6.2x10-8 Kaz - 30 6x 10-13 Ka, Kagykz Hence the most abundant species is Ho por