Question

Now calculate the [H+] and pH of a 0.00725 M solution of nitrous acid.

Nitrous acid (HNO2) is a weak acid that partially dissociates as follows, with a Ka = 0.0004266: HNO2 + H20 + H30+ + NO2 a) Calculate the [h+] and pH of a 1.73 M solution of nitrous acid. [H+]=49) 0.0270 b) pH = 49 1.57 c) Now calculate the [H+] and pH of a 0.00725 M solution of nitrous acid. 49) 0.0016 d) 49 1.7

Answer 1

Given data ka= 0.000 4266 ( = 0.00 725 M Solution According to Ostwald's formula of weak electrolyte. Ka = 22.c where a = degree of dissociation, & e 0.000 4266 No.00 725 a = 10.0508414 2 = 0.242572 Concentration of [ht] = d.c. = 0.242572 X0.00725 [H+] = 0.00176 PH = -log [ht] = -log[0-00176] pH = 2.75