8)Electrochemistry

Question 1

E) EMF of the cell

Answer 1

Ecell = Ered + E oxi

Question 2

E) Gibbs free energy

Answer 2

ΔG0 = -nFE0

Question 3

E) pH meter emfs

Answer 3

Eel = k’’ + 0.0592pH
where E= mV

Question 4

E) Nernst

Answer 4

E = E0 - 2.303RT/ nFlogQ

Question 5

D) Laws of oxidation numbers

Answer 5

OILRIG - oxi involves loss, red involves gain.
1) Free element = 0
2) Total in molecule/ion = charge of molecule/ion
3) Gr 1 and 2 = +1 and +2
4) F = -1; Cl = -1 (unless bonded to Oxy or flour)
5) H= +1
6) O = -2 (unless bonded to oxy oe flour)
7) Gr 7A, 6A and 5A = -1, -2 and -3 when bonded to metals