Question

A 150.0 mL sample of 0.080 M Ca2+ is titrated with 0.080 M EDTA at pH 9.00. The value of log Kr for the Ca2+-EDTA complex is 10.65 and the fraction of free EDTA in the Y- form, ay, is 0.041 at pH 9.00. What is K/, the conditional formation constant for Ca²+ at pH 9.00? What is the equivalence point volume, Ve, in milliliters? ml V = Ve= Calculate the concentration of Ca²+ at V = { v. [Ca2+1 = Calculate the concentration of Ca2+ at V = V. [Ca²+] = Calculate the concentration of Ca2+ at V = 1.IV. [Ca2+1 =

Answer 1

AMs P-i M2y4 +y My- m ca) 0.041 11 caiven TEOTAT formation constand. k My7 logkf 10.65 1010.65 K-Kaye (uosBr -4,47 Xlo ot if pH is fised Here pH-g, o = 4, 47x1o X 0.0u O.183X1010 (b EDTA f Ca react to fom a 1:1 mplx. /so mL, o.0g0m Ca trhreded wth 0io 8amEDTA 0 equralen Point shoulo be Ca M,v, M2V_ EDTA 5o me Ve ISo me ( Concentection Ca at V ve Ca 2 2 rnmales mole EDTA ve (ISo) mex Oi08M 6m mb Reacio Ca- EDTA + EDTA Tabl Ca2 Betore 6-6 Atto 12-) 6 Mn 0.0267 225m nCca 7.ome+ 75 me) 0.0267 M al v v

(d) v- ve P-2 mobs Ca2: 152mex o. 12ms /2 ma ED7A SD ma xo.08 Imole Ca2 +EDTA Ca.Eb TA /2 mon (2mmd /2 mmele Af first ts losk like ca7-but It because Not K io Not tina (K= 4.47x1o) S0 ther o a dettle fre Cat Ca EDTA tcaJrEDTA tca EDTA ca = EDTAJX alwaye fom an Table 12mmede (1So 1S)me - 0.04M Takime mto accomtthia back xn b04-X Keff X 2 20Oy KS 1831 0104 1-82X109 0,0467s Xio 0Ca2= 0.04 675X1O ta 4.7s KIOM Calendy Calelta) 4- at v Ve (es Ca at v= {1ve (Atr ualena point) mile Ca misEDTA ISO mex o08 M12 mle 13.2 m Le Ca2 EDTA 13.2 Ca.EDTA Befne 12 -12 12 -12 4tter 1.2 2. Our obse bd Con - 3.8095X1M CEDTAT 2 mnel s+15p)me Ca EDTA 2 mmol - O03549M 315mL . Bit reaetion n back urel direchon Ca 0+ rEDTAT 3.809 Sx1o+x Ca EDTA -3 oB809-2

P-2 At equlubnun 0.62809- 3.801K10) o.03809 ay3.809X O.03809 10 10 1.83 X1 5.46109 80 Ca2 5.46X1M at velIve After quivelens Pomf
EDTA is a Hexaprotic system. EDTA with Ca+2 form complex in 1:1. All steps are in equilibrium so Consider backward reaction for the concentration calculation.