Question

17. What is the dominant form of aspartic acid (a triprotic acid represented as H3A) at a pH of 2.5 in a water sample (pKal = 1.990, p 22 = 3.900, PK23 = 10.002)? a. H3A and H2A are equal c. H2A b. Н3А d. HA2- 18. What would you expect the pH level in a 25.0 mL sample of 0.22 M hydrazoic acid given its Ka = 2.6 x 10-S? a) 2.62 b) 5.42 c) 7.00 d) 8.97 €) 11.22 19. A 25.0 mL water sample is titrated with a 0.0180 M NaOH solution using methyl orange indicator. The equivalence point is reached when 37.0 mL of the base is added. The concentration of H* in the sample was a) 0.0121 b) 1.83 x 10-5 c) 0.0266 d) 0.0365 e) 0.0175 M.

Answer 1

E dy) Pn a pkai So. 205 (PH) ů clasest frean Pka;= logg So. H₂A (ar) - H₂A (aq) + 1₂0 cha) will be dominant oan. and ka, LLLL Кa, &. LH24] [130] [13A] soo M3 A li deminent forma option, b Å correcto UUU @huw +x th 6006UULUULE ② Ngh (aq) - Naion) + 130t Lag) 0.22 0 0 -X 0.22-2 x x ka = [N3] [n30"} [134] 2.68105 x² (0.22-2) .: 2164105 (ka) (C21 to 0.22-3-0022 c² = 6. 22 x 206420-5 I= 20 39410-3

- [1304] = x= 2.39 810 ²M, Pur - log (2.39 810-3) Pu= 2062 option @ is correcto /// / 130+ + Naoneart matcaa) + H₂O) appled POAC Rule. moles of not moles of Naon cofficient Cofficient [1₂0] XV ngot 0.08 x 37ml. //000 [12 ot] 25 ml = 0.018 x 37ml. (1304) = 0.0266M Thank you, May it help you :)