Question

Consider the titrtation of 25.0mL of 0.0100M Sn2+ by 0.0500M Ti3+ in 1 M HCL, using Pt and Saturated Calomel Electrodes to find the endpoint.

F=96486.7 Cmol

E0 Sn4+/Sn2+ =0.15V

E0 TI3+/TI+ = 1.28

Esce = 0.241V

R=8.3141 J K Mol


(a) Write the balanced reaction.

Sn4+ + 2e- <--> Sn2+

TI3+ <--> TI+ + 2e-


Sn2+ + Tl3+- -> Sn4+ + Tl+

(b) Write two different half reactions for the net cell reaction.

I'm assuming this means

Sn4+ + 2e- <--> Sn2+ E0= 0.15V


TI3+ <--> TI+ + 2e- E0= 1.28 V

(c) Write the two nernst equations for the net cell reaction

Prior to the equivalence point, the equation would be;

E=1.28+RT/F ln(TI3+/TI+)-SCE (0.241)

Where TI3+/TI+ = Conc. products/reactants.

After the equivalence point, reaction then becomes,

E=0.15 + RT/F ln(Sn4+/Sn2+) - SCE

(D) calculate E at the following volumes of TI3+ : 1.00mL, 2.50mL, 4.90mL, 5.00mL,5.10mL and 10.0mL

This is the section I am having difficulty with, if anyone could help, thanks.