MEDIUM
Earn 100

Which of the following is oxidised by oxygen in acidic medium?

50% studentsanswered this correctly

Important Questions on Redox Reactions and Electrochemistry

HARD
Consider the change in oxidation state of Bromine corresponding to different emf values, as shown in the diagram below:
Question Image
Then, what is the species undergoing disproportionation?
EASY

In the following passage there are blanks, each of which has been numbered. There are questions given below the passage and for each question, four words are suggested, one of which fits the blank appropriately. Find out the appropriate word in each case.

Whenever I go into a bank, I feel scared. Everybody and everything that I see there (1) ____ me. As for the manager the sight (2) ____ him simply terrifies me and (3) ____ me want to runaway (4) _____ I can. As soon as I (5) ____ the door of the bank I lose my head (6) ____ when I try to do any (7) ____ there, I behave like an idiot. I cannot explain (8) ____ for this but that is how it (9) ____ has been that is how it is (10) ____.

Select the most appropriate option for blank No. 10.

EASY

Given the standard half-cell potentials E° of the following as

ZnZn2++2e-;  E°=+0.76 V

FeFe2++2e-;  E°=+0.41 V

Then the standard e.m.f. of the cell with the reaction Fe2++ZnZn2++Fe is

HARD
Some standard electrode potentials at 298 K are given below:

Pb2+/Pb-0.13 V

Ni2+/Ni-0.24 V

Cd2+/Cd-0.40 V

Fe2+/Fe-0.44 V

To a solution containing 0.001 M of X2+ and 0.1 M of Y2+, the metal rods X and Y are inserted (at 298 K) and connected by a conducting wire. This resulted in dissolution of X. The correct combination(s) of X and Y, respectively, is(are)

(Given: Gas constant, R=8.314 J K-1 mol-1, Faraday constant, F=96500 C mol-1)

MEDIUM
Identify the reaction from following having top position in electrochemical series according to their standard electrode potential.
MEDIUM

Calculate the standard cell potential (in V) of the cell in which the following reaction takes place:

Fe2+ aq+Ag+aqFe3+aq+Ag(s)

Given that
EAg+/Ago=x V
EFe2+/Feo=y V
EFe3+/Feo=z V

MEDIUM

In which metal container, the aqueous solution of CuSO4 can be stored?

ECu3+/Cu0=0.34 V

EFe/Fe2+0=0.44V,EAl/A3+0=1.66V

ENi/N2+0=0.25V,EAg+/Ag0=0.80V

EASY
Given
ECl2/Cl-o=1.36V, ECr3+/Cro= -0.74V
ECr2O72-/Cr3+o=1.33V, EMnO4-/Mn2+o=1.51V.
Among the following, the strongest reducing agent is:
MEDIUM
Consider the following standard electrode potentials (Eo in volts) in aqueous solution:
ElementM3+/MM+/MAl-1.66+0.55Tl+1.26-0.34
Based on these data, which of the following statements is correct?
MEDIUM
Four successive members of the first row of transition elements are listed below with atomic numbers. Which one of them is expected to have the highest EM3+/M2+o value?
EASY
The standard emf of the cell ZnZn2+Ag+|Ag is 1.56 V. If the standard reduction potential of Ag is 0.8 V, the standard oxidation potential of Zn is
MEDIUM
Given that the standard potentials Eo of Cu2+/Cu and Cu+/Cu are 0.34V and 0.522V respectively, the Eo of Cu2+/Cu+ is:
MEDIUM

What will be the oxidation potential for the following hydrogen half cell at 1bar pressure and 25ºC temperature?

PtH2(g) 1bar HCl(aq)pH=3

EASY
What will be the half-cell potential of a hydrogen electrode acting as an anode and dipped in a solution of pH=2 ?
MEDIUM
Four metals W,X,Y and Z have standard electrode potential as -0.13 V,-0.85 V,-0.25 V and +0.22 V respectively. The most reducing metal is
HARD
Given below are the half - cell reactions :

Mn 2 + + 2 e - Mn  ;  E = - 1.18 V 2 Mn 3 + + e - Mn 2 +  ;  E = + 1.51 V

The E for 3 Mn 2 + Mn + 2 Mn 3 + will be :
MEDIUM
A variable, the opposite external potential (Eext) is applied to the cell Zn | Zn2+ 1MCu2+ 1 M| Cu, of potential 1.1 V. When Eext<1.1 V and Eext>1.1 V, respectively electrons flow from
HARD

The standard reduction potential for Cu2+/Cu is +0.34 V. Calculate the reduction potential at pH=14 for the above couple.

Ksp of CuOH2=1×1019