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Electrochemistry- Theory 1 (in Hindi)
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Theory

Vishwa Vivek Sharma
verified & star educator|| IIT-JEE NEET|| 5+ year experience|| hindi & English medium ||Chemistry || youtube- "Sharmaji education"

U
Unacademy user
Jg
how is avg height and avg depth in figure calculated pls explain
sir is this sufficient for neet plz reply
Yes
sir please bring more and more questions .......
Ok ji
Thank you so much 😊
  1. unacademy Vishwa Vivek Sharma teaches live onplus . All Live and Structured courses Lessons by all top Educators IIT JEE plus 30+ hours of live lessons everyday Weekly Quizzes & Doubt-clearing Structured courses in English and Hindi 20+ top educators Use Referral Code ervishwav vek for 10% off your Unacademy Plus Subscription New courses published every month Learn more Get subscription O Downloaded


  2. Physical Chemistry


  3. Physical Chemistry IT-JEE/NEET Electrochemistry Follow me for Advance Chemistry Er. Vishwa Vivek Sharma


  4. Physical Chemistry IT-JEE/NEET Metallic Conductors Flow of electricity undergoes without decomposition of substance. Electricity produced due to movement of electrons (no flow of matter) Electrolytic Conductors Flow of electricity undergoes with decomposition of substance Electricity produced due to movement of ions (flow of matter). Follow me for Advance Chemistry Er. Vishwa Vivek Sharma


  5. Physical Chemistry IT-JEE/NEET Conductance When potential difference is applied between two electrodes, migration of ions start from one electrode to another. Positively charged ions i.e., cations move towards negatively charged electrode i.e., cathode (cations move towards cathode). Negatively charged ions i.e., anions move towards positivelycharged electrodei. ., anode(anionsmove towards anode). Due to movement of these ions, electricity flows and ease of electricity flow is known as conductance. Follow me for Advance Chemistry Er. Vishwa Vivek Sharma


  6. Physical Chemistry IIT-JEE/NEET - Unit -ohmor siemens (in SI unit) ohm Resistance: If voltage applied is E and current flow is I, then resistance is volt Ohm's law] ampere Specific resistance : Resistance of conductor is directly proportional to its length (1) and inversely proportional to its area of cross section (a). Ra - specific resistance-ohm cm where p is called specific resistance or resistivity Follow me for Advance Chemistry Er. Vishwa Vivek Sharma


  7. Physical Chemistry IIT-JEE/NEET Property Definition Specific conductance Equivalent conductance Molar conductance Reciprocal of specific resistance or Conductance produced by Conduction produced by all conductance of solution of 1 cm length all the ions of 1 g equivalent the ions of 1 mol electrolyte and 1 cm2 area of cross-section. electrolyte in a given solution. in a given solution. (lambda) Representation k (kappa) Formula Am (lambda) 1000 Normality 1000 Molarity p Ra ohm-1 cm1 siemens m eg ohm1 cm2 eq1 siemens m2eq ohm-1 cm2 mol-1 siemens m2 mol-1 Unit SI unit -1 Follow me for Advance Chemistry Er. Vishwa Vivek Sharma


  8. Physical Chemistry IT-JEE/NEET Relation between equivalent conductance (A) and molar conductance (A where n equivalent factor of the electrolyte which is equaltototalchargeonanions/cations/basicityofacids/ acidity of bases. Also, n Molecular mass Equivalent mass Factors Affecting the Conductance of Electrolyte Solutions Conductance o extent of ionization oc temperature. Follow me for Advance Chemistry Er. Vishwa Vivek Sharma


  9. Physical Chemistry IT-JEE/NEET Nature of Electrolytes The strong electrolytes undergo complete ionization and hence show higher conductivities since they furnish more number of ions. Whereas weak electrolytes undergo partial ionization and hence show comparatively low conductivities in their solutions. lonic Size and Mobility Conductivity c Ionic mobility o Ionic size Conductivity Viscosity of solvents Follow me for Advance Chemistry Er. Vishwa Vivek Sharma


  10. Physical Chemistry IT-JEE/NEET Concentration The specific conductance (x) increases with increase in concentration of solution as the number of ions per unit volume increases - Whereas, both the equivalent conductivity and molar conductance increase with decrease in concentration (i.e., upon dilution) since the extent of ionization ncreases. Since the concentration decreases, one can expect decrease in equivalent conductivity due to decrease in available number of ions per unit volume. However the increase in volume (V) factor more tharn compensates this effect. The volume must be increased in order to get one equivalent of electrolyte since the concentration is decreased. Hence the net effect is increase in equivalent conductivity. Follow me for Advance Chemistry Er. Vishwa Vivek Sharma


  11. Physical Chemistry IIT-JEE/NEET Debye-Huckel-Onsager Equation It is possible to determine the equivalent conductivities of electrolytes in water at given concentration by using Debye-Huckel-Onsager equation where, Am molar conductivity at infinite dilution. molar conductivity at given concentration. c-electrolyte concentration A and B constants that depend only on known quantities such as temperature, the charges on the ions and the dielectric constant and viscosity of the solvent. straight line slope for weak electrolytes withnegative is obtained when the equivalent conductivity values (e) of strong electrolytes are plotted against square roots of different concentrations for strong electrolytes Ne (Vc) The equivalent conductivity at infinite dilution (A can be determined by extending this straight line to zero concentration. Follow me for Advance Chemistry Er. Vishwa Vivek Sharma


  12. Physical Chemistry IIT-JEE/NEET However, the equivalent conductivity of weak electrolytes increases steeply at very low concentrations and hence their limiting values (Aeg) cannot be determined by extrapolating the Ac to zero concentration. * Therefore, Ae for weak electrolytes is obtained by using Kohlrausch law of independent migration of ions Kohlrausch's Law The molar conductance of an electrolyte at infinite dilution is the sum of the molar conductances of cations and anions 0 and are called ionic conductances of cation and anion at infinite dilution respectively Consider a reaction: A,Bv> xA yB- AY+ Follow me for Advance Chemistry Er. Vishwa Vivek Sharma


  13. Physical Chemistry IT-JEE/NEET Electrochemical Cells Electrochemical cell is a system in which two electrodes are fitted in the same electrolyte or in two different electrolytes which are joined by a salt bridge. Types of electrochemical cells: Electrolytic cell : It is a device which converts electrical energy into chemical energy i.e., electrical energy is supplied to the electrolytic solution to bring out redox reaction Galvanic cell : It is a device which converts chemical energy to electrical energy ie, electrical energy is produced with the help of redox reaction Half cell and half-cell reaction of galvanic cell: Galvanic cell consists of two half cells. The reaction occuring in half-cell is called half cell reaction. Follow me for Advance Chemistry Er. Vishwa Vivek Sharma


  14. Physical Chemistry IIT-JEE/NEET EMF of the cell can be calculated from the values of electrode potential of the two half-cells constituting the cell by using following methods: Ecellox (anode) + Eped (cathode) When only reduction potential taken into account E (cathode) - Efed (anode Efight - Eleft When only oxidation potential taken into account, Egeli = Eox (anode)-Eox (cathode) Standard hydrogen electrode (SHE) or Normal hydrogen electrode (NHE): Standard hydrogen electrode (SHE) or normal hydrogen electrode (NHE) is used as reference electrode whose electrode potential is 298 K. In standard hydrogen gas electrode H2 gas at 1 atm is passed through 1 M HCl solution at 298 K. Platinum wire acts as inert electrode through which flow of electrons takes place Depending upon whether NHE acts as anode or cathode in a given cell, is represented as Pt, H2 (1 atm) H (1 M) or H (1 M)IH2(1 atm), Pt respectively. 0.00 at Follow me for Advance Chemistry Er. Vishwa Vivek Sharma


  15. Physical Chemistry IIT-JEE/NEET ' 2H+ + 2e Sn4++ 2e Cu2++e Cut+e- I22e Fe3+ e Ag e Br22e Cl2+ 2e- 0.13 0.00 + 0.15 +0.15 +0.52 +0.53 Fe 0.77 +0.80 +1.08 2Cl- + 1.36 02(g) + 4H'(ap + 4e- 2H2O + 1.23 +1.50 2+ 1.82 +2.87 -> H2 Sn2+ Cut Cu 21 2Br Au3+ 3e C03+ + e- F2+ 2e -Au 2p- Follow me for Advance Chemistry Er. Vishwa Vivek Sharma


  16. Physical Chemistry IIT-JEE/NEET Nernst Equation Electrode potential of an electrode can be obtained by Nernst equation Consider a reaction : M+ne M Nernst equation: E E RT, M In 1+ For pure solid or liquid or gas at 1 atm pressure, the molar concentration is taken as unity: [M] 1 In M_2.303RT log nt 1n 0.0591 E Eo where E-electrode potential undergiven concentration of M" ions. n- number of electrons involved in electrode reaction, [M"* concentration of M"+ ions. Follow me for Advance Chemistry Er. Vishwa Vivek Sharma


  17. Physical Chemistry IIT-JEE/NEET For a cell Zn) Cu (ap) > Zn2*(ap) + Cup) Ecell -Ecell In general, aA + bB-w xX + yY log2+ 2 ul 0.0591 XY log Eqiibrium constant from Nernst equation: Equilibrium is achieved when potential of cell is zero. ce 0.0591, IZn2+ og ! cell 0.0591 cell = log K, at 298 K. Kc tells about the extent of reaction. Follow me for Advance Chemistry Er. Vishwa Vivek Sharma


  18. Physical Chemistry IIT-JEE/NEET Dry cell Lead storage battery Secondary cell Rechargable. Used in automobiles Pb : anode PbO2 : cathode Reactions: At anode: 1.Primary cell 2. Not rechargable 3. Zn: anode 4. Reactions: C rod: cathode At anode: At cathode: 2MnO2(s)+ 2NH4a)At cathode: (a ) 4 (aq.) PbSO4)2e 2eMn2O3) Pb029)+ SO,2(a)+ PbSOs 2H2O Follow me for Advance Chemistry Er. Vishwa Vivek Sharma


  19. Physical Chemistry IT-JEE/NEET Factors which promote corrosion Reactivity of metal More active metals are readily corroded Presence of air and moisture : Air, moisture and gases like SO2 CO2 catalyse the process of corrosion Presence of impurities: Pure metals do not corrode. Presence of electrolytes : Electrolytes in water increase the rate of corrosion Strains in metals: Corrosion takes place rapidly at bends, scratches, nicks and cuts in the metal. Follow me for Advance Chemistry Er. Vishwa Vivek Sharma


  20. Physical Chemistry IT-JEE/NEET Electrical protection (cathodic protection) This method is used when iron articles are in contact with water such as underground water pipes, storage tanks, canals, etc. The article of iron is connected with more active metals like magnesium, zinc or aluminium which acts as anode. Iron pipe act as cathode in this case. Follow me for Advance Chemistry Er. Vishwa Vivek Sharma