Advertisements
Advertisements
प्रश्न
How many faradays of electricity are required to produce 6 g of Mg from MgCl2?
Advertisements
उत्तर
Mg2+ + 2e- → Mg(s)
1 mole Mg2+ equals 2 mole e- for electrosis
1 mole Mg required 2 Faraday electricity
rquired 2 faraday electricity
6g Mg will require = `(2 xx 6)/24`
= 0.5 F
APPEARS IN
संबंधित प्रश्न
Can you store copper sulphate solutions in a zinc pot?
Arrange the following metals in the order in which they displace each other from the solution of their salts.
\[\ce{Al, Cu, Fe, Mg}\] and \[\ce{Zn}\]
Construct a labelled diagram for the following cell:
`Zn|Zn^(2+)(1M)||H^+(1M)|H_(2(g,1atm))|Pt`
Write cathode and anode reaction in a fuel cell.
Among Zn and Cu, which would occur more readily in nature as metal and which as an ion?
Why cannot we store AgNO3 solution in copper vessel?
For the electrochemical cell:
\[\ce{M | M+ || X- | X}\];
\[\ce{E^{\circ}_{{M^{+}/{M}}}}\] = 0.44 V,
\[\ce{E^{\circ}_{X/X^-}}\] = 0.33 V
Which of the following is TRUE for this data?
What is the SI unit tor electrochemical equivalent?
A solution of Cu(NO3)2 is electrolyzed between platinum electrodes using 0.1 Faraday electricity. How many moles of Cu will be deposited at the cathode?
If one mole electrons is passed through the solutions of CrCl3, AgNO3 and NiSO4, in what ratio Cr, Ag and Ni will be deposited at the electrodes?
At 25°C, the emf of the following electrochemical cell.
\[\ce{Ag_{(s)} | Ag^+ (0.01 M) | | Zn^{2+} {(0.1 M)} | Zn_{(s)}}\] will be:
(Given \[\ce{E^0_{cell}}\] = −1.562 V)
Zinc can be coated on iron to produce galvanized iron but the reverse is not possible. It is because ____________.
Assertion: pure iron when heated in dry air is converted with a layer of rust.
Reason: Rust has the compositionFe3O4.
A certain current liberated 0.504 gm of hydrogen in 2 hours. How many grams of copper can be liberated by the same current flowing for the same time through copper sulphate solution.
A gas X at 1 atm is bubbled through a solution containing a mixture of 1 MY− and 1 MZ− at 25°C. If the reduction potential of Z > Y > X, then ______.
Define anode
Define cathode
Why is anode in galvanic cell considered to be negative and cathode positive electrode?
Can Fe3+ oxidises bromide to bromine under standard conditions?
Given: \[\ce{E^0_{{Fe^{3+}|Fe^{2+}}}}\] = 0.771 V
\[\ce{E^0_{{Br_{2}|Br^-}}}\] = −1.09 V
Two metals M1 and M2 have reduction potential values of −xV and +yV respectively. Which will liberate H2 and H2SO4.
Reduction potential of two metals M1 and M2 are \[\ce{E^0_{{M_1^{2+}|M_1}}}\] = −2.3 V and \[\ce{E^0_{{M_2^{2+}|M_2}}}\] = 0.2 V. Predict which one is better for coating the surface of iron.
Given: \[\ce{E^0_{{Fe^{2+}|Fe}}}\] = −0.44 V
For the cell \[\ce{Mg_{(s)}|Mg^{2+}_{( aq)}||Ag^+_{( aq)}|Ag_{(s)}}\], calculate the equilibrium constant at 25°C and maximum work that can be obtained during operation of cell.
Given: \[\ce{E^0_{{Mg^{2+}|Mg}}}\] = −2.37 V and \[\ce{E^0_{{Ag^{+}|Ag}}}\] = 0.80 V
Which of the following statement is correct?
Which of the following statement is not correct about an inert electrode in a cell?
Use the data given in below find out the most stable ion in its reduced form.
`"E"_("Cr"_2"O"_7^(2-)//"Cr"^(3+))^⊖`= 1.33 V `"E"_("Cl"_2//"Cl"^-)^⊖` = 1.36 V
`"E"_("MnO"_4^-//"Mn"^(2+))^⊖` = 1.51 V `"E"_("Cr"^(3+)//"Cr")^⊖` = - 0.74 V
`E_(cell)^Θ` for some half cell reactions are given below. On the basis of these mark the correct answer.
(a) \[\ce{H^{+} (aq) + e^{-} -> 1/2 H_2 (g); E^Θ_{cell} = 0.00V}\]
(b) \[\ce{2H2O (1) -> O2 (g) + 4H^{+} (aq) + 4e^{-}; E^Θ_{cell} = 1.23V}\]
(c) \[\ce{2SO^{2-}_{4} (aq) -> S2O^{2-}_{8} (aq) + 2e^{-}; E^Θ_{cell} = 1.96V}\]
(i) In dilute sulphuric acid solution, hydrogen will be reduced at cathode.
(ii) In concentrated sulphuric acid solution, water will be oxidised at anode.
(iii) In dilute sulphuric acid solution, water will be oxidised at anode.
(iv) In dilute sulphuric acid solution, \[\ce{SO4^{2-}}\] ion will be oxidised to tetrathionate ion at anode.
`E_(cell)^Θ` = 1.1V for Daniel cell. Which of the following expressions are correct description of state of equilibrium in this cell?
(i) 1.1 = `K_c`
(ii) `(2.303RT)/(2F) logK_c` = 1.1
(iii) `log K_c = 2.2/0.059`
(iv) `log K_c` = 1.1
Can absolute electrode potential of an electrode be measured?
Depict the galvanic cell in which the cell reaction is \[\ce{Cu + 2Ag^+ -> 2Ag + Cu^{2+}}\]
Consider the following diagram in which an electrochemical cell is coupled to an electrolytic cell. What will be the polarity of electrodes ‘A’ and ‘B’ in the electrolytic cell?
How will the pH of brine (aq. \[\ce{NaCl}\] solution) be affected when it is electrolysed?
Match the terms given in Column I with the items given in Column II.
| Column I | Column II |
| (i) Λm | (a) intensive property |
| (ii) ECell | (b) depends on number of ions/volume |
| (iii) K | (c) extensive property |
| (iv) ∆rGCell | (d) increases with dilution |
Assertion: ECell should have a positive value for the cell to function.
Reason: `"E"_("cathode") < "E"_("anode")`
Assertion: Mercury cell does not give steady potential.
Reason: In the cell reaction, ions are not involved in solution.
Which of the following statements about galvanic cell is incorrect
A current of 2.0 ampere passed for 5 hour through a molten salt deposits 22 g of the metal (Atomic mass = 177). The oxidation state of the metal in the metal salt is
Given the data at 25°C
\[\ce{Ag + I- -> AgI + e-}\]; E° = – 0.152 V
\[\ce{Ag -> Ag+ + e-}\]; E° = – 0.800 V
The value of log Ksp for AgI is ______.
The correct order of the mobility of the alkali metal ions. In aqueous solultion is
In a Daniel cell, ______.
Read the passage given below and answer the questions that follow:
|
Oxidation-reduction reactions are commonly known as redox reactions. They involve transfer of electrons from one species to another. In a spontaneous reaction, energy is released which can be used to do useful work. The reaction is split into two half-reactions. Two different containers are used and a wire is used to drive the electrons from one side to the other and a Voltaic/Galvanic cell is created. It is an electrochemical cell that uses spontaneous redox reactions to generate electricity. A salt bridge also connects to the half-cells. The reading of the voltmeter gives the cell voltage or cell potential or electromotive force. If \[\ce{E^0_{cell}}\] is positive the reaction is spontaneous and if it is negative the reaction is non-spontaneous and is referred to as electrolytic cell. Electrolysis refers to the decomposition of a substance by an electric current. One mole of electric charge when passed through a cell will discharge half a mole of a divalent metal ion such as Cu2+. This was first formulated by Faraday in the form of laws of electrolysis.
|
- Is silver plate the anode or cathode? (1)
- What will happen if the salt bridge is removed? (1)
- When does electrochemical cell behaves like an electrolytic cell? (1)
- (i) What will happen to the concentration of Zn2+ and Ag+ when Ecell = 0. (1)
(ii) Why does conductivity of a solution decreases with dilution? (1)
OR
The molar conductivity of a 1.5 M solution of an electrolyte is found to be 138.9 S cm2mol-1. Calculate the conductivity of this solution. (2)
The number of moles of electrons passed when the current of 2 A is passed through a solution of electrolyte for 20 minutes is ______.
Galvanic cell is a device in which ______.
What should be the signs (positive/negative) for \[\ce{E^0_{cell}}\] and ΔG0 for a spontaneous redox reaction occurring under standard conditions?
The cell constant of a conductivity cell is 0.146 cm-1. What is the conductivity of 0.01 M solution of an electrolyte at 298 K, if the resistance of the cell is 1000 ohm?
What is an electrochemical cell? What does it consist of?
