Electro Chem

Question 1

Helmholtz double layer or electrical double layer

Answer 1

Metal rod is in contact with sol of its ions…two reac are possible
Metal-ions ; ions-metals
Opp tendencies = equilibrium
Possibilities for position of equilibrium
1. Fr>br, electrode surface develops a layer of +be charges which attracts -be a layer of -be charges at interface developing an electrical double layer
2. Br>fr

Question 2

Classification of electrodes

Answer 2

Metal metal ion
Metal metal salt ion
Gas
Oxidation reduction 
Ion selective

Question 3

Standard hydrogen electrode

Answer 3

Consists glass tube with pt foil
Placed in bell shaped glass jacket fused at top
It has h2 inlets at top Nd has inlets at bottom
Pt is dipped in h+ Iona and h2gas is bubbled through gas inlet
H2 gas gets absorbed on pt foil and establishes equilibrium with h+ ions

Question 4

Limitations of she

Answer 4

Can’t be used at stp always
Pt is used-so can’t be used al the time
Can’t use in labs as it is poison
Can’t be used in presence of oxidising agents

Question 5

Calomel electrode

Answer 5

Metal metal salt ion
Consists mercury mercurous chloride kcl sol
Mercury bottom
Paste of Hg Nd hg2cl2 above Hg
Space abound paste is filled with kcl sol of known conc
Pt wire is immersed into mercury to obtain electrical contact
Abide Nd cathode depending on nature of other electrode

Question 6

Diff galvanic cell Nd electolytic cell

Answer 6

Gal converts chemical into electrical
Redox reac occurring at electrode is spontaneous
Electrodes are dissimilar metals
Two electrolytes in a sol are connected by a salt bridge
-be electrode anode

Question 7

Nernst equation

Answer 7

Gives relationship between single electro potential Nd standard electrode potential through conc of metal ions at particular temp
Vanthoff’a reaction isotherm
-^G=-^G0-RTlnK