Question

Consider the following data on some weak acids and weak bases: acid base name formula name hydrocyanic acid HCN 4.9 x 10 formula methylamine CH, NH 4.4 x 10 hydroxylamine HONH, 1.1 10 hypochlorous acid HCIO 3.0 x 108 Use this data to rank the following solutions in order of increasing pH. In other words, select a 'l' next to the solution that will have the lowest pH, a 2' next to the solution that will have the next lowest pH, and so on. solution 0.1 M Nal choose one 0.1 M Nacio choose one 0.1 M HONH Br choose one 0.1 4 KCN choose one X 5 ?

Answer 1

O.LM Nal 6. IM HONH B9 = [c] HI + NaOH - NaI +H₂O 1 strong O IM KCN strong Hor + HONH₂ => HG NH₂ Br salt 2] acid base Ineutral) strong auld weak base salt HCN +KOH -> KON Ho weak strong salt neutral salt kg Ob HONH = 1-2x10 8 so acid borse pkb= -log Kb= -log (tlx108) = 7.96 HON: Ka 4-941010 OLM Nacto -10) for this salt pH formula ka-log kg -109 (4-8 x10 / Hdlo + Naot - Naclot to weak strong salt pH t [pkw_pkb_log c] pka_ 9-31 acid base for this salt pH formula Ką of Hclo= 3x10 8 pH t {14-7.96 -log(64)] plt + [ pk wapka Lage] pka_-log ka = log (3x108) = 7.52 I pt - 3.52 4 pkw 214 pH = 1 { 14+ 9.31+ 10g (0-1)] formula for this salt pH pH = 2 [ple wapka +log c] pH = 11.155 pH t [14+7052+ log (0-1)] = 10.26 o-LM HONH, Br <o.LM NaI <o.lm Naclo <o.IM KCN (3.52) - (1) (10-26) (11-155)

pH: formula's for salt's weak acid + strong barse -salft to pH = ± [pfw + pka + loge] strongacid & weakbase salf tho pt = ₃ [ pk w plebe_loge