Question

please answer 1 and both parts of 2

1. Which one of the following sets of compounds is not characteristic of a buffer? a. HNO3 with NaNO b. NaH POwith Na2HPO: C. NH; with NHACI d. CH3COOH with NaCH3COO 2. What is the pH of the following buffer solutions? a. 0.45 M NH3 and 0.55 M NH-CI. K. (NH3) = 1.8 x 105 b. 0.36 M HCOOH and 0.55 M KHCOO. K. (HCOOH) = 1.8 x 104

Answer 1

Solution : 1² Buffer Buffer is. ar mixture of weak auid or weak base and its salt. a. HNO A Naną. HNO is a strong acid and Nano its salt. bet and required weak and or base Hng is strong and so it is not a buffer. b. Naha poq and with Nag HP It is mixture of weak acid (HaHa Pot). & its scelt (Nag HPO4). C. 9H3 a with NHAU. NH3 is weak base and NHall its scelt and both combination is formed basic buffer. d. CH₂cool with NaCH₃Coo. CH₃Coon is weak and and NaCH₃ Coo its salt, and they formed alidic buffer. So, option, a is correct answer. na. HNO3 with Nanoz. b. No H₂ poe with hot pog. C. NH3 with NHQU. do CH₂ cool with Nachoo Solution 2: a) Given Data Concentration of NH3 0.45M Con Quaơn 4 NGQs o'65 M Ky = $8x10-5 pko = -log(ko)

By applying pko= log (18x185) pko = 4.74 Handerson - Hasselbalch equation for buffer. por = pky + tlog [rall] basic [base] рои parken 4.74+ log [0.55M] [o 45M] posts 4.74 + 0.087.15 pon = 4.8275 post-4.83 ph+ pot = 14 pH= t4 - pon =14-4.83 9.17 ри 9.17 so b). Giren Data Concentration of HCOOH) = 0:36M Concentration of KHCOo= 0.55M Korea 1.8x10-4 pka= -log (ka) plea = -log (1.8818-4) pka = 3-74 By applying Handerson Havel balch equation for acidic buffer.

pH= pka + log Isalt] Cacid] pH= 3.74+ log [0:55M] TO EM] Ph: 3:14+ 184 pH: 3.924 ph= 3.92 30, ph=3.92