Electrochemistry

FeO42- +2.0 V Fe3+ 0.8 V Fe2+ -0.5 V Fe0 In the above diagram, the standard electrode potentials are given in volts (over the arrow). The value of E (FeO42-/Fe2+) is :

1. 1.2 V
2. 2.1 V
3. 1.4 V
4. 1.7 V

Standard electrode potentials for a few half cells are mentioned below : E Cu2+/Cu = 0.34 V, E Zn2+/Zn = -0.76 V E Ag+/Ag = 0.80 V, E Mg2+/Mg = -2.37 V Which one of the following cells gives the most negative value of G ?

1. Zn | Zn2+(1M) || Ag+(1M) | Ag
2. Ag | Ag+(1M) || Mg2+(1M) | Mg
3. Zn | Zn2+(1M) || Mg2+(1M) | Mg
4. Cu | Cu2+(1M) || Ag+(1M) | Ag

Which of the following electrolyte can be used to obtain H2S2O8 by the process of electrolysis ?

1. Concentrated solution of sulphuric acid
2. Dilute solution of sodium sulphate.
3. Acidified dilute solution of sodium sulphate.
4. Dilute solution of sulphuric acid

A solution of aluminium chloride is electrolysed for 30 minutes using a current of 2 A. The amount of the aluminium deposited at the cathode is . [Given : molar mass of aluminium and chlorine are 27 g mol-1 and 35.5 g mol-1 respectively. Faraday constant = 96500 C mol-1]

1. 1.660 g
2. 1.007 g
3. 0.336 g
4. 0.441 g

Given below are two statements : In the light of the above statements, choose the correct answer from the options given below :

1. Both Statement I and Statement II are true
2. Both Statement I and Statement II are false
3. Statement I is true but Statement II is false
4. Statement I is false but Statement II is true

The molar conductivity for electrolytes A and B are plotted against C1/2 as shown below. Electrolytes A and B respectively are: [figure]

1. A - weak electrolyte B - weak electrolyte
2. A - weak electrolyte B - strong electrolyte
3. A - strong electrolyte B - strong electrolyte
4. A - strong electrolyte B - weak electrolyte

The standard reduction potentials at 298 K for the following half cells are given below : Cr2O72- + 14H+ + 6e- 2Cr3+ + 7H2O, E = 1.33 V Fe3+(aq) + 3e- Fe E = -0.04 V Ni2+(aq) + 2e- Ni E = -0.25 V Ag+(aq) + e- Ag E = 0.80 V Au3+(aq) + 3e- Au E = 1.40 V Consider the given electrochemical reactions, The number of metal(s) which will be oxidized by Cr2O72-, in aqueous solution is .

Match List I with List II Choose the correct answer from the options given below:

1. A-III, B-I, C-IV, D-II
2. A-I, B-II, C-III, D-IV
3. A-IV, B-III, C-I, D-II
4. A-II, B-III, C-IV, D-I

Which out of the following is a correct equation to show change in molar conductivity with respect to concentration for a weak electrolyte, if the symbols carry their usual meaning :

1. m - m + AC 12 = 0
2. m2C + Ka m 2 - Ka m m = 0
3. m - m - AC 12 = 0
4. m2C - Ka m 2 + Ka m m = 0

The emf of cell Tl | Tl+ (0.001 M) | | Cu2+ (0.01 M) | Cu is 0.83 V at 298 K. It could be increased by :

1. increasing concentration of Tl+ ions
2. increasing concentration of Cu2+ ions
3. increasing concentration of both Tl+ and Cu2+ ions
4. decreasing concentration of both Tl+ and Cu2+ ions