Electrochemistry.

Question 1

Order

Answer 1

Li K Ba Sr Ca Na Mg Ae Mn Zn Cr Fe Cd Co Ni Sn Pb H2 Cu I2 Ag Hg Br2 Pt O2 Cl2 Acl Fe

Question 2

Relation between Gibbs free energy and emf of the cell

Answer 2

−ΔG=nFE⁰(cell)

; F= Faradays constant =96500

Question 3

Gibbs Helmholtz Eq

ΔG=?

Answer 3

ΔG = ΔH+ T[d(ΔG)/dt]

; valid for constant pressure

Question 4

Gibbs Helmholtz eq

dE(cell)/dt=?

Answer 4

dE(cell)/dt= ΔH/nFT + E(cell)/T

Question 5

Relation between entropy change and emf of the cell

Answer 5

ΔS=nF(dEcell/dt)

Question 6

Nearst Eq E(cell)=?

Answer 6

E(cell)=
E(cell)=E⁰(cell)-0.0591/n x log₁₀ K
;K= reaction quotient
n= electrons transferred in cell reaction

Question 7

Faradays first law w=?

Answer 7

w=zit
; z= Atomic number/ nF
n= electrons transferred in cell reaction

Question 8

Faradays second law w=?

Answer 8

w=QE/F
; E= Equivalent weight
Q= charge passed
w= amount liberated / deposited on electrode

Question 9

In electrochemistry , conductivity k=?

Answer 9

k= l/a x G
; k= conductivity
G = conductance
l/a = cell constant

Question 10

In electrochemistry , molar conductance Λ(m)=?

Answer 10

Λ(m)= k x 1000/c
; c= concentration of cell
Λ(m) = molar conductance
k= conductivity

Question 11

Debye Huckel Onsages Eq

Λ(m)= ?

Answer 11

Λ(m)=Λ⁰(m) - A√c
; c = concentration of sol.
Λ⁰(m)= Molar conductivity on infinite dilution
Λ(m)= Molar conductivity

Question 12

Electrolytic reaction of NaCl (aq)

Answer 12

At anode : 2Cl-= Cl2 + 2e-

At cathode: 2H20 + 2e= H2 + 2OH-

Question 13

Electrolytic reaction of CuSo4

Answer 13

At anode: 2H20= O2+4H+ +4e-

At cathode: Cu+2 + 2e- = Cu

Question 14

Electrolytic reaction of Na2So4

Answer 14

At anode: 2H20= O2+4H+ + 4e-

At cathode: 2H20+ 2e- = H2+ 2OH-

Question 15

Electrolytic reaction of NaCl dilute

Answer 15

At anode: 2H20= O2+ 4H+ +4e-

At cathode: 2H20+2e= H2+2OH-

Question 16

Electrolytic reaction of NaCl(aq) using Hg electrode

Answer 16

At anode: 2Cl-=Cl2+2e-

At cathode: Na+ + e-= Na

Question 17

Electrolytic reaction of CuSo4 using Cu electrodes

Answer 17

At anode: Cu= Cu+2 + 2e

At cathode: Cu+2 +2e-= Cu

Question 18

Electrolytic reaction of AgNO3 using Ag electrode

Answer 18

At anode: Ag= Ag+ + e

At cathode: Ag+ e-= Ag

Question 19

Electrolytic reaction of H2SO4 (aq)

Answer 19

At anode: 2H20= O2 + 4H+ +4e-

At cathode: 2H20+2e-= H2 + 2OH-

Question 20

Electrolytic reaction of a dry cell

Answer 20

At anode: Zn= Zn+2 +2e-

At cathode: 2MnO2 + 2NH4+ +2e- = Mn2O3+ 2NH3 +H20

Question 21

Electrolytic reaction of a Mercury cell

Answer 21

At anode:Zn + 2OH- = ZnO + H20 +2e-

At cathode: HgO +H20 +2e- = Hg + 2OH-

Question 22

Electrolytic reaction of a lead storage battery

Answer 22

At anode: Pb + SO₄2-= PbSO4 + 2e-

At cathode: PbO2 + SO₄2- + 4H+ = PbSO4 + 2H2O

Question 23

Electrolytic reaction of a nickel cadmium battery

Answer 23

At anode: Cd + 2OH- = Cd(OH)2 + 2e-

At cathode: Ni(OH)3 + e- = Ni(OH)2 + OH-

Question 24

Electrolytic reaction of a fuel cell

Answer 24

At anode: 2H2 + 4OH- = 4H20 + 4e-

At cathode: O2 + 2H20 + 4e- = 4OH-