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the quantity of electricity required to reduce 12.3g of nitro benzene to aniline assuming 50% current efficiency is
rusting 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
Trick to learn electrochemical series.
Its very urgent due to chemistry first term on Saturday.......
a current of 0.965 ampere is passed through 500ml of 0.2M solution of ZnSO4 for 10 min . the molarity of Zn+2 after deposition of zinc is
2) 0.5M3) 0.194M
Zn rod is placed in 100ml of 1M CuSO4 solution so that molarity of Cu+2 changes to 0.7M . the molarity of SO4-- at this stage will be
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.
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
E(standard)cell for the cell, Zn|Zn2+(aq)||Cu2+(aq)|Cu is 1.1V at 25degreesC., the equilibrium constant for the reaction Zn+Cu2+--------- Cu + Zn2+(aq) is the order of
1- 10^+18 2- 10^+37
3- 10^-28 4- 10^-37
Total charge required for oxidation of 2 moles Mn3O4 into MnO42- in the presence of alkaline medium is:
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
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
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
aluminium metal cannot be produced by electrolysis of aqueous solution of aluminium salt.give reason.
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
A 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
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
Two half cell reactions of an electrochemical cell are given below:
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
CONDUCTIVITY OF 0.12M CUSO4 SOLUTION AT 298K IS 1.8*10 RAISE TO -2 S CM . CALCULATE ITS EQUIVALENT CONDUCTIVITY.
Represent the cell in which the following reaction takes place
Mg(s) + 2Ag+(0.0001M) ------ Mg2+(0.130M) + 2Ag(s)
Calculate its E(cell) if E0(cell)=3.17 V.
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% H2SO4by 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.
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) CuCl2 (3) Cu(NO3)2 (4) CuSO4
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) Pb2+ coverts toPb (2)Pb2+coverts toPb4+ (3)Pbcoverts toPb2+(4) Pb4+ converts to Pb2+
Q4. Standard cell voltage for cell Pb/Pb2+||Sn2+/Snis -0.01V. If the cell is to exhibit Ecell=0, the value of log[Sn2+]/[Pb2+] 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 25oC. 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) | H2(P2) |Pt
(1) RT/ F ln P1 / P2(2)RT/ 2FlnP1/ P2(3)RT/ FlnP2/ P1(4)RT/ 2FlnP2/ P1
For what concentration of Ag+ will the EMF of te given cell be zero at 25 C .If the concentration of Cu2+ is 0.1 M. EoAg+ = 0.80v and Eo Cu2+ = 0.34 V
in SHE , the pH of acid solution should be
PbO2 ------- PbO dG(298k)
SnO2 ------- SnO dG(298k) 0
Most probable oxidation state of Pb and Sn will be
1- Pb4+ , Sn4+ 2- Pb4+,Sn2+
3- Pb2+, Sn2+ 4- Pb2+, Sn4+
can 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.
IN electrolysis of NaCl when Pt electrode is taken then H2 is liberated at cathode while with Hg Cathode it forms Sodium Amalgam
1- Hg is more inert than Pt
2- More voltage is required to reduce H+ at Hg than at Pt
3- Na is dissolved in Hg while it does not dissolve in Pt.
4- Conc. of H+ ions is larger than when Pt electrode is taken
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?
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?
One gm metal M3+ was discharging by the passage of 1.81 *1023 electrons.What is the atomic weight of metal?
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
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)
Equinormal solution of two weak acids , HA(pKa= 3) and HB (pKb = 5) are each placed in contact with standard hydrogen electrode at 25oC. When a cell is construsted by interconnecting them through a salt bridge , find the emf of the cell.
Answer : E = 0.059
Calculate the emf of the cell in which the following reactions takes place:
Ni(s) + 2Ag+(0.002M) ------- Ni2+(0.160M) +2Ag(s)
Given that E0(cell) = 1.05 V
1.5 A current is reduced to 10 minutes in a solution of CuSO4,
How many mass of copper is deposited on the cathode?
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
phosphorus pentoxide , P4O10 has each phosphorus linked to
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.
Please explain briefly .
The number of degenerate orbitals present in an energy level of H-atom characterized by E=-R/16 where R is the Rydberg constant ?
the electrolysis of an acetate solution produces ethane and carbon dioxide acc to the reaction
2CH3COO- gives C2H6+2CO2+2e-
The efficiency of reaction is 82%. What volume of C2H6 and CO2 would be produced at 27oCand 740mm pressure if a current of 0.5 ampere is passed through the solution for 7hours?
Which change requires an oxidising agent?
1- 2S2O3 ---------- S4O6(2-)
2-Zn2+ -------------- Zn
3- ClO- --------- Cl-
4- SO3 -------- SO4(2-)
how to know?
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.
The electrolysis of MnO2 is carried out from a solution of MnSO4 in H2SO4 (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 MnO2?
or reaction , 4Al(s) + 3O2(g) + 6H2O + 4OH- ===== 4[Al(OH)-]; Eocell = 2.73 V. If ÎGof(OH-)= -157kj/mol and ÎGof(H2O) = -237.2 kj/mol , determine ÎGof[Al(OH-)4].
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