Advertisements
Advertisements
Question
E°cell for the given redox reaction is 2.71 V
Mg(s) + Cu2+ (0.01 M) → Mg2+ (0.001 M) + Cu(s)
Calculate Ecell for the reaction. Write the direction of flow of current when an external opposite potential applied is
(i) less than 2.71 V and
(ii) greater than 2.71 V
Advertisements
Solution
Ecell = `"E"°_"cell" - (0.0591)/(n)log ["Mg"^(2+)] // ["Cu"^(2+)]`
= `2.71 - (0.0591)/(2)log (0.001)/(0.01)`
=`2.71 - 0.0295 xx (-1)`
= `2.7395 "V"`
i) When an external potential is less than 2.71 then current will flow from copper to magnesium.
ii) When an external potential is greater than 2.71 then current will flow from magnesium to copper.
APPEARS IN
RELATED QUESTIONS
Among Zn and Cu, which would occur more readily in nature as metal and which as an ion?
How many faradays of electricity are required to produce 6 g of Mg from MgCl2?
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.
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
`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.
How will the pH of brine (aq. \[\ce{NaCl}\] solution) be affected when it is electrolysed?
If the half-cell reaction A + e– → A– has a large negative reduction potential, it follow that:-
If 0.5 amp current is passed through acidified silver nitrate then in 100 minutes the mass of silver, deposite on cathode is (eq. wt. of silver nitrate + 108).
In a solution of CuSO4, how much time will be required to precipitate 2 g copper by 0.5 ampere current?
What are electrochemical reactions?
