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Syllabus

the quantity of electricity required to reduce 12.3g of nitro benzene to aniline assuming 50% current efficiency is

1) 115800C

2) 57900C

3) 231600C

4) 28950C

Calculate the cell potential for the following cell:

Pb/Pb

^{2+ }(1x10^{-3 }M) // Pt, 1/2 Cl_{2 }(1 bar) / Cl^{- }(0.1 M)GIVEN: E

^{0 }Pb^{2+}/Pb= -0.13V and E^{0}1/2 Cl_{2}/Cl^{-}= 1.358Vrusting of iron is quicker in saline water than ordinary water.why

The equilibrium constant of the reaction

Cu(s) +2Ag(aq) ---- Cu2+(aq) +2Ag(s) E(standard)cell = 0.46V at 298K is

1- 2 x 10^10 2- 4 x 10^10

3- 4 x 10^15 4- 2.4 x 10^10

a current of 0.965 ampere is passed through 500ml of 0.2M solution of ZnSO

_{4}for 10 min . the molarity of Zn^{+2}after deposition of zinc is1) 0.1M

2) 0.5M3) 0.194M

Trick to learn electrochemical series.

Its very urgent due to chemistry first term on Saturday.......

in a electrochemical cell , when external potential is applied which is less then the 1.1v that current flows from right to left and when it is higher then the 1.1v then the direction of current is reversed ,why is it so? explain

A voltaic cell is set up at 25C with the half-cells Al | Al3+ (0.001 M) and Ni | Ni2+ (0.50 M).

Write the equation for the reaction that occurs when the cell generates an electric current and determine the cell potential.

_{3}(aq) producing Cu2+ ions. Explain the difference in behaviour.Given:-

E

^{o}_{Cu2}_{+/Cu-}= 0.34VE

^{o}_{Cl2/ 2Cl-}= 1.36VNO

_{3}- + 4H^{+}+ 3e^{-}→ NO + 2H_{2}OE

^{o}_{NO3-/ NO}= 0.97Vwhat is principle and workin of galvanic cell??????????

Total charge required for oxidation of 2 moles Mn

_{3}O_{4}into MnO_{4}^{2-}in the presence of alkaline medium is:The electrolysis of MnO

_{2}is carried out from a solution of MnSO_{4}in H_{2}SO_{4}(aq.). If a current of 25.5 ampere is used with a current efficiency of 85%, how long would it take to produce 1 kg of MnO_{2}?Please explain briefly .For the disproportionation of copper 2Cu+------ Cu2+ + Cu, E(standard)cell is (given E for Cu2+/Cu is 0.34V and E for Cu2+/Cu+ is 0.15V)

1- 0.49V 2- -0.19V

3- 0.38V 4- -0.38V

What will be decrease in concentration of Ni 2+ when reaction Co + Ni 2+(0.1 M ) = Co 2+(0.01M) + Ni reaches equilibrium ? E Co2 |Co = -0.28 V and E Ni2+|Ni = -0.23v.

Zn rod is placed in 100ml of 1M CuSO

1) 0.8M2) 1M3) 0.7M4)1.8M_{4}solution so that molarity of Cu^{+2}changes to 0.7M . the molarity of SO_{4}-- at this stage will bephosphorus pentoxide , P4O10 has each phosphorus linked to

aluminium metal cannot be produced by electrolysis of aqueous solution of aluminium salt.give reason.

1. a) calculate gibbs free energy for the following reaction at 25 degree celcius Au(s)+Ca(2+ 1 aq)----------------- Au(3+ aq 1M)+Ca(s)

EAu(3+)/Au=+1.50 V; E Ca(2+)/Ca=-2.87 V

b)Predict whether the reaction will be spontaneous or not

_{2}using Hg cathode. how long shud current of 5 ampere be passed to prepare 12% Cd-Hg amalgam on a cathode of 2 gm Hg(Cd=112.4(molecular mass))A spoon is to be plated by silver during the electrolysis of Ag(CN)2 using spoon as cathode. Surface area of the spoon is 140cm2 and thickness is 0.01cm; calculate the time required for electroplating using current of 0.012 amp . given that the density of silver is 10.5g/ml.

Two half cell reactions of an electrochemical cell are given below:

MnO (aq ) +8H+ (aq ) + 5e Mn2+ (aq) + 4H2 O( l), E 1.51V Sn 2+(aq) +Sn 4+(aq) + 2e , E0 =0.15 VConstruct the redox equation from the two half cell reactions and predict if this reaction favours formation of reactants or product shown in the equation._{4}solution by passing current of 1 A for 16 minute and 5 secondA hydrogen gas electrode is made by dipping platinum wire in a solution of HCl of pH = 10 and by passing hydrogen gas around the platinum wire at one atm pressure, The oxidation potential of electrode would be

1- 0.59V 2- 0.118V

3- 1.18V 4- 0.059V

Represent the cell in which the following reaction takes place

Mg(s) + 2Ag

^{+}(0.0001M) ------ Mg^{2+}(0.130M) + 2Ag(s)Calculate its E

_{(}_{cell)}if E^{0}_{(cell)}=3.17 V.can we store aluminium sulphate in zinc pot?give reason.

CONDUCTIVITY OF 0.12M CUSO4 SOLUTION AT 298K IS 1.8*10 RAISE TO -2 S CM . CALCULATE ITS EQUIVALENT CONDUCTIVITY.

1.0.01 M CH

_{3}COOH2.0.01 M NH

_{4}OH3.0.01 M NaCl

4.0.01 M K

_{2}SO_{4}^{+ }in an aqueous solution containing Cu^{2+}=1.0 M so that both the metals can be deposited on the cathode simultaneously. Given that E^{0}_{cu/cu}^{2+}^{=}-0.34 and E^{0}_{Ag}^{+}_{/Ag = 0.812V,T= 298K}_{4}per L is 91.0 W^{-1}cm^{2}eq^{-1}. Its conductivity would be?Please show with steps.................

Standard free energies of formation (in KJ/mol) at 298K are -237.2, -394.4, and -8.2 for H2O(l), CO2(g) and pentane (g) respectively. The value of E(standard)cell for pentane oxygen fuel cell is?

1- 0.0968V 2- 1.968V

3- 2.0968V 4- 0.059V

calculate the concentration of OH– ions in the solution after the electrolysis.

Q1. During electrolysisof aqueous solution of a salt pH in the space near one of the electrodes is increased. Which of the following salt solution was electrolyzed?

(1) KCL(2) CuCl

_{2}(3) Cu(NO_{3})_{2}(4) CuSO_{4}

Q2. The ionic mbilityof alkali metal ions in aqueous solution is maximum for

(1) Na

^{+ }(2) K^{+ }(3) Rb^{+} (4) Li^{+}Q3. During the recharging of lead acid storage cell the reaction at anode is

(1) Pb

^{2+ }coverts toPb (2)Pb^{2+}coverts toPb^{4+ }(3)Pbcoverts toPb^{2+}(4) Pb^{4+ }converts to Pb^{2+}Q4. Standard cell voltage for cell Pb/Pb

^{2+}||Sn^{2+}/Snis -0.01V. If the cell is to exhibit E_{cell}=0, the value of log[Sn^{2+}]/[Pb^{2}^{+}] should be(1) 0.33 (2) 0.5 (3) 1.5 (4) -0.5

Q5.The hydrogen electrode is dipped in a solution of pH = 3 at 25

^{o}C. The reduction potential of the electrode would be(1) 0.177V (2) 0.087V (3) -0.177V (4) 0.059V

Q6. What would be the emf of the given cell?

Pt | H2(P1) | H

^{+}_{(aq)}| H_{2}_{(P2)}|Pt(1) RT/ F ln P

_{1}/ P_{2}(2)RT/ 2FlnP_{1}/ P_{2}_{}(3)RT/ FlnP2/ P_{1}(4)RT/ 2FlnP2/ P_{1}Caculate the emf of the cell in which the following reaction takes place :

Ni(s) + 2Ag

^{+}(0.002 M) ----- Ni^{2+}(0.160 M) + 2Ag(s)Given that E

^{0}_{(cell)}= 1.05 V.For what concentration of Ag+ will the EMF of te given cell be zero at 25 C .If the concentration of Cu

^{2+}is 0.1 M. E^{o}Ag^{+}= 0.80v and E^{o}Cu^{2+}= 0.34 Vcan 1M NiSO4 be stored in a vessel made up of copper ?

given: E(Ni2+/Ni ) = -1.20V and E (Cu2+/Cu) =0.34V

my doubt- as I know (plz correct if am wrong) that E (cell) finally should come out to be positive . if E is positive then reaction will be spontaneous. so the ans will beYES , hence proved.

but if reaction is occuring between NiSO4 and Cu , then HOW NiSO4can be stored in Cu????

plzz clear it.

During the electrolysis of water 4 mol of electrons were transferred from anode to cathode. the total volume of gases produced at STP will be approximately

In electrolysis of aqueous NaCl, what volume of Cl2 (g) is produced in the time that it takes to liberate 5.0 litre if H2 (g)? Assume that both gases are measured at STP.

Al2O3 is reduced by electrolysis at low potentials and high currents . If 4.0 x 10^4 amperes of current is passed through molten Al2O3 for 6 hours, What mass of aluminium is produced?( Assume 100% current efficiency, At. mass of Al= 27g mol^-1)

1- 1.3 x 10^4g

2- 9 x 10^3 g

3- 8.1 x 10^4 g

4- 2.4 x 10^5 g

The equivalent conductance of M/32 solution of a weak monobasic acid is 8.0 mhos cm^2 and at infinite dilution is 400 mhos cm^2. The dissociation constant of the acid is

1- 1.25 x 10^-4 2- 1.25 x 10^-5

3- 1.25 x 10^-6 4- 6.25 x 10^-4

How can we find antilog using log table ?In the Example 3.2 in the NCERT, log K

_{C}= 15.6For value of Antilog(15.6), how we have to proceed ?

I don't know the basic logarithm too...Please tell which formula to apply ? Do we have to use log table ?

Given

1- Cu2+ + 2e- ----- Cu, E(standard) = 0.337V

2- Cu2+ + e- ------- Cu+ , E(standard) = 0.153V

Electrode potential , E(standard) for the reaction , Cu+ + e- ------ Cu, will be

1- 0.38V 2- 0.52V

3- 0.90V 4-0.30V

^{-}_{cell}is E^{-}_{Cathode}-E^{-}_{anode ,}is n't it tht E_{cathode}should be greater than that of anode so that reduction takes place at cathode , thenE^{-}_{cell}will be positive but then why is in some case it negative?Two electrolytic cells containing AgNo3 solution and dil.H2SO4 solution are connected in series.A steady current of 2.5 amp was passed till 1.078g of silver was deposited.

a)How much electricity was produced?

b)What was the weight of O2 liberated?

what is the value of F [faraday]?

The electrode potentials for Cu2+ + e- -------- Cu+(aq) and Cu+(aq) + e- ------- Cu(s) are +0.15V and +0.50V respectively. The value of ECu2+/Cu will be?

1- 0.15V 2- 0.5V

3-0.325V 4- 0.650V

Conductivity of 0.00241M acetic acid solution is 7.896 ×10-5 S cm-1. Calculate its molar conductivity in this solution. If ^m for acetic acid is 390.5 S cm2 mol-1, what would be its dissociation constant?

During the discharge of lead storage battery the density of sulphuric acid fell from 1.294 to 1.139gcm

^{-3}. The sulphuric acid of density 1.294gcm^{-3}is 39% H_{2}SO_{4}by mass and that of density 1.139gcm^{-3 }is 20% by mass. The battery holds 3.5L of acid and the volume remains practically constant duing discharge. Calculate the no. of amper-hours for which battery must have been used.Equinormal solution of two weak acids , HA(pKa= 3) and HB (pKb = 5) are each placed in contact with standard hydrogen electrode at 25

^{o}C. When a cell is construsted by interconnecting them through a salt bridge , find the emf of the cell.Answer : E = 0.059

What type of a cell is the lead storage battery? Write the anode and the cathode reactions and the overall reaction occurring in a lead storage battery while operating

Calculate the emf of the cell in which the following reactions takes place:

Ni(s) + 2Ag

^{+}(0.002M) ------- Ni^{2+}(0.160M) +2Ag(s)Given that E

^{0}_{(cell)}= 1.05 Vare galvanic cell and daniell cellare same? if not then what is the difference between them???????????

in SHE , the pH of acid solution should be

1) 7

2) 14

3) 0

Resistance of 0.2M solution of an eletrolyte is 50ohm. The specific conductance of the solution is 1.4S/m. The resistance of 0.5 M solution of the same electrolyte is 280ohm. The molar conductivity of 0.5 M solution of the electrolyte in Sm2/mol is?

1.5 A current is reduced to 10 minutes in a solution of CuSO4,

How many mass of copper is deposited on the cathode?

how many coulombs are required to produce

a)20g of calcium from molten CaCl2?

b)40g of Al from molten Al2O3?

One gm metal M3+ was discharging by the passage of 1.81 *1023 electrons.What is the atomic weight of metal?

Crack this if u can.

A cell whose resistance when filled with 0.1 M kcl is 200 ohm, is measured to be 6400 ohm, when filled with 0.003M nacl solution. All measurements are at 298 K. what is the equivalent conductance of nacl solution.

The number of degenerate orbitals present in an energy level of H-atom characterized by E=-R/16 where R is the Rydberg constant ?

PLEASE ANSWER FAST...in two vessel containing 500ml water , 0.5 mol of aniline (Kb = 10

^{-9}) and 25 mmol of HCl are added seperately . Two hydrogen electrodes are constructed using these solutions. Calculate the emf of cell made by connecting them appropriately.Answer :0.395V

Please explain briefly ._{4}a current of 9.65 A passed for hour. Calculate the PH of the solution after electrolysisdefine conductivity of an electrolytic solution

_{4}^{--}ions produces S_{2}O_{8}^{--}^{}.Assuming 75% current efficiency what current should be employed to achieve a production rate f 1 mole of S_{2}O_{8}^{--}per hour?ethyl glycol is used in car radiators. why?

The reaction, N2(g) + O2(g) 2NO(g) contributes to air pollution whenever a fuel is burnt in air at a high temperature. At 1500 K, equilibrium constant K for it is 1.0 × 105. Suppose in a case [N2] = 0.80 mol L1 and [O2] = 0.20 mol L1 before any reaction occurs. Calculate the equilibrium concentrations of the reactants and the product after the mixture has been heated to 1500 K.

how may minutes it take to plate out 5.0 g of Cr from cr2(So4)3 solution using a current of 1.50 A? (At. Weight ; Cr = 52)

_{3}And CuSO_{4 }SOLUtion in series. if mass of Ag deposited is 1.08g find the mass of copper deposited^{0}_{Ni2+/Ni }= - 0.25 V, E^{0}_{Cu2+/Cu}= + 0.34 V ]the conductivity of pure water in a conductivity cell with electrodes of cross-sectional area 4cm

^{2 }placed at a distance 2 cm apart in 8 x 10^{-7}S cm^{-1}. calculate the resistanceof conductuvity cell ...........or reaction , 4Al(s) + 3O

_{2}(g) + 6H_{2}O + 4OH^{-}===== 4[Al(OH)^{-}]; E^{o}_{cell}= 2.73 V. If Î”G^{o}_{f}(OH^{-})= -157kj/mol and Î”G^{o}f(H_{2}O) = -237.2 kj/mol , determine Î”G^{o}_{f}[Al(OH^{-})_{4}].Please explain briefly .