Question

Fluoroacetic acid, C2H3FO2, occurs naturally in at least 40 plants found in Australia, Brazil and in Africa, notably in "Gifblaar" which is one of the most poisonous plants found in South Africa. The compound is highly toxic and causes convulsions and ventricular fibrillation and has been used to poison rats. If the Ka of this acid is 2.57 x 10 determine the (H'), the (OH), the pH and the poH for a 0.05 M solution of this acid.

Answer 1

s: The ionisation of naturally occurring fluoroacetic acid in aqueous medium can be expressed according to the following equilibmund; FCH₂ -"COH + H₂O FC Hy-eot H₂ot Ataparticular tempesestuore, the equilibrium conutart of the following tonization, k offuscoo-1 [H2ot 1 [fH CCOM]CH120] -9. Ionisation Constant of trifuoroacetic acid, Kas [fHyC200-] (113071 fro nt [FH2Ccool] - 2057x10-3 The concerifnation of this acid Solutions 20:05(M) 9-10p(2.57x10-3) Cei 2.59 At equilibmicam, Fhze-cool +th0 FH,CC00 +4207 C-CA (M) ca ca . [H3ot) a ca to dissociation extend of the acid erste o Jeka a, -log[hzot] = -logka - Iloge (taking log and resign) 2. pka = -logka

-. pH ={pka - kloge 2422.59 - £xlc70.05 = 1.9455 (H*] > Jeika > Jo.05 x 2.57X10-3 o r d) = 0.01133578(M) At 25c, POH > 14-pH = 14-1.9455 = 12:0545 os, -tog [OH-] = 12.0846 Co. [OH-] = 10 – 12.0545 > 8-8206x10–13 (M) o Thees from 0.05(M) Solution of their fluconaceticocid, CH+] -0.01133578(M) COH 128.8206x10-13(M), PH 1-9455 and pol> 12.0545.