Question

What is the pH of 0.595 M Na₂SO₃(aq) at 25 °C? (K_a1 = 1.2E-2, K_a2 = 6.2E-8)

Answer 1

- Ans - Calculation of pH of 0.595 M Na, son como ka, of Has0 = 1.2 x 102 Kad of heS0g = 6.2X10- Initial 0.595M Come Conc. son cap) + HOCA H 59,Coylt of caq? At equillo 0.595-2 Rp = [50 Caps] [oHº cap] - 0 B [sor caq) ] ko for the reaction is related to kang of 450 ko = kw 1x10" 1 Kog (of so) 6.2 410-8 kg = ): G1X00+ 1 {ka. ks = kw} Put the value of th in equation o 161 X107 = x x x 1 (0.595-x) = 0.161 X10 0.595-% -0.595 1.618167 = 32 0.595 a = √ 1.61810* x 0.595 x = 10.957 x10-7 x = 79.57 X1008 - 3.09 Xroy M

] is 3.09810 4 M Concentration of [or [+] = kw our] = 1x1019 3.09810-4 3.09 x 70-y = 0.3236 X1010 Now, Calculate the pH of the solution- pH = -log [+] 3 - log [ 0.3236 * 10-10) = -log(6.3236) – log to?" - log (0.3236)+10 =-(-0.489) +10 = 0.49 + 10 pH = 10.49 So, the pH of 0.595 M Naso Caq) at 25c is 10.49