Question

The electrochemical cell shown can be used to calculate the formation constant (Kf) for a metal (M) and EDTA. The cell has a potential of −0.266 V. The right half‑cell contains a metal ion (M2+) with a standard reduction potential of −0.236 V.

M2+ + 2e −−⇀↽−M(s) E°=−0.236 V

Voltmeter H, (9) PH2=0.40 bar Salt bridge 30 mL of 0.010 M citric acid 70 mL of 0.010 M NaOH 30 mL of 0.010 M M2+ 70 mL of 0.010 M EDTA (Qy4_=0.81 at pH 11) pH 11.0 (buffered)

Citric acid has three pKa values: 3.128, 4.761, and 6.396. Calculate the Kf for the metal–EDTA complex.

Kf=

Answer 1

page:01 Answer:- According to the given information, to calculate the key for the metal-ESTA Complex, Given, Cell voltage, Ecell = -0.266 standard reduction potential of half reaction, fo cell -0.236V. pressure of Hain left cell, Pha ouoban. oresht half-cell racion, Mat + 2€ = MISI € 1.-0.236v left half-cell reaction, 9H+ tae H219), e : 0.OV es cell voltage og vighet half-cell reaction using wernistean. Fix a to - o.orges log

page:09 Et 64 5401986) – Dogana long terting 40.936) - O05916 O ... celt voltage of left half-cell reaction essing nennst ean E- : to- o.osals log file has 16--1000) - Dople longer than - © 3. cell voltage expoumpon, |fcell - Ex- C - Substfferte the values of Et and en rom eqn and in Eceu =(-0.296) – o os que log in - 0100 + opet og er Ecele = (-01236 ) - 0.05al6 tog {Hitje QUO(42+7 -0.266 = (-0136)- o-osals log Cits 2 OruD[M2+

page:03 the hydrogen ion concentration (rit} is calculated from the pH value of the solution - from coluen the sucction Ends worth Cetric acid (H3A) i. Coneiden left half-cell swachon is, O H₂A tot HaAt it bao pka - 3.198 Before ounction, mmol Naot a Tomi X 0.00M 1. - [640mmol avab 4 and - mnol AizA - 3000.000 [0.20mmol ham After ouachon, mmol NaOH 0.40 -0.30 O.Uomol mmol Han 0:30

pageiou * Hann tot > HA2- + Hgo pka nu.761 mmol NaOH = 0:00-0:30 z Olomol mmol /A2 -0.30 HAZ* + OH --> M3+ + H908. pka = 6:396 remol HA&- = 0.20 mmol A3-2010 apply the formula for pH in reaction ③. pH = pka3 aloq r mmol A3-] mmol HA21 pH ={6.346) + log ( 20 ) pH 6.095 (H*}: 10-P? [ht] : 10-6.095

page:05 {{*} = 803x16m Substitute this valeve og[H+] in gqin @ --O266 5 -00236 -0.05916 fogl 18.03x003) 2 01 O UOCM2+] ] -0.366 + 0.936 -0.0591 col D. MOC MAPA] ] -0.03 - - 0.69958 log (16612416'2) - 0:03 a 10g (+06+2x1612) -0.02958 1 04019898 3 = 10g (1,612X10") 1612. xlo12 (124) = 0.096783 1 [H2+] = 6000341094 . Consider caction between Edia and 124 M+2 +EOTA Kts My 2- Here, MYS is the metal Enta complex. :

page:06 1 kg = (My2-} 1 [**] &yu-Cepralgerald - (EDTAber initial mol of EOTA - initial mol of Mn24 Total volume. My 2 - initial mol of Hazt Total volume LEOTA] final (70X0.010)-(30x0.010) loo (ferral final) - 0.00uoM mya.. 0:30/100 1 (Myan] = 0.0030M substitute the values of (Hypt), doyu- , [My ?-) and EOTA Cfinal] in Equation Re: 0.0030M 0 3X100M X 015180.0000 2 105uxion To's The Ecra metal complex Kf losuxlo"