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T) Refer to the galvanic cell below (the contents of each half-cell are written

ID: 698281 • Letter: T

Question

T) Refer to the galvanic cell below (the contents of each half-cell are written beneath each 15 pts 1.0 x 103 MN 10 MHC 1.0MHCI AgC(s) The Standard reduction potentials are as follows. Ag+ + e-Ag(s) Eo = 0.30 V Ni2 + 2e-Ni(s) E=-0.23 V i) Calculate the standard cell potential E ii.) Write the net cell reaction. ii) What is the value of Q, the reaction quotient, for this cell reaction? Note Kp for Agci- 1.6 × 10-10 and the Ag+ in equilibrium with AgCl(s). iv.) What is the cell potential E at 25°C for this cell as read on the digital voltmeter? v) Calculate the free energy

Explanation / Answer

(i)

E0cell = 0.80 - ( - 0.23 ) = 1.03 V

(ii)

Cell reaction is,

Ni (s) + 2 Ag+ (aq.) ------------> Ni2+ (aq.) + 2 Ag (s)

(iii)

Ksp of AgCl = [Ag+][Cl-]

Ksp = S2

S = sqrt.Ksp = sqrt.(1.6*10-10) = 1.26 * 10-5 M

Q = [Ni2+] / [Ag+]2

Q = 1 * 10-3 / (1.26 * 10-5)

Q = 62.5

(iv)

Ecell = E0cell - (0.0591 / n) * LogQ

Ecell = 1.03 - (0.0591 / 2) * Log(62.5)

Ecell = 0.977 V

(v)

deltaG = - n F Ecell = - 2 * 96500 * 0.977 = - 188561 J = - 188.6 kJ