Question

Calculate the pH and the equilibrium concentration of S^2- in a 7.90×10^-2 M hydrosulfuric acid solution, H₂S (aq).

For H₂S, K_a1 = 1.0×10^-7 and K_a2 = 1.0×10^-19

Answer 1

1. The two stage ionisation of this is a o his 4 H2O ² H30t + H5 Km [Mgo") [Hs') slotroz [Hz 5] J H.S 4 H₂O H304 + s2- [1120") [624] [H5) = 21.0 x1619 Kaza! яко. Коя >> Қар , kо ми е сям цder the first ionisation is the main source of Hot and hence we can write [H3 09 ] [H5") di Kas - [H3ot)? [H25] [#30t] - J xas x (H. 57

:. Less") - Голо+ хэзо хр?- - 8. 89 х 10 * ч • pt E-toz #zt'] - - log (8-89 хто ) 1. PH . 4. os і

I again putting the relation [H2or] - [ts] in the expression of Kaz we get- Kara ["130"] [s²-) ..[145] ce [Dzoty CR-) Гң аят [52- a kar E lrox1019 m