In electrolysis of NaCl when Pt electrode is taken then H2 is liberated at cathode while with Hg cathode it forms sodium amalgam because :
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. Concentration of H+ ions is larger when Pt electrode is taken.
If mercury is used as cathode in the electrolysis of aqueous NaCl solution, the ions discharged at cathode are:
1. H+
2. Na+
3. OH-
4. Cl-
Standard Reduction electrode potential of three metals X, Y, and Z are -1.2 V, +0.5 V and -3 V respectively. The reducing power of these metals will be :
1. | Y > X >Z | 2. | Z > X > Y |
3. | X > Y > Z | 4. | Y > Z > X |
A gas X at 1 atm is bubbled through a solution containing a mixture of 1MY- and 1MZ- at 25C. If the reduction potential of Z > Y > X, then:
1. Y will oxidise X and not Z
2. Y will oxidise Z and not X
3. Y will oxidise both X and Z
4. Y will reduce both X and Z
The solution of CuSO4 in which copper rod is immersed is diluted to 10 times, the reduction electrode potential:
1. increases by 0.030 V
2. decreases by 0.030 V
3. increases by 0.059 V
4. decreases by 0.059 V
A solution containing one mole per litre each of Cu(NO3)2, AgNO3, Hg2(NO3)2 and Mg(NO3)2 is being electrolyzed by using inert electrodes. The values of standard electrode potentials in volt (reduction potentials) are,
Ag+ /Ag = 0.80 V, /2Hg = 0.79 V,
Cu2+/Cu = +0.34 V and Mg2+/Mg = -2.37 V
With increasing voltage, the sequence of deposition of metals on the cathode will be:
1. Ag, Hg, Cu, Mg
2. Mg, Cu, Hg, Ag
3. Ag, Hg, Cu
4. Cu, Hg, Ag
The highest electrical conductivity of the following aqueous solution is of:
1. 0.1 M acetic acid
2. 0.1 M chloroacetic acid
3. 0.1 M fluoro acetic acid
4. 0.1 M difluoro acetic acid
Standard reduction potentials at 25C of Li+/Li, Ba2+/Ba, Na+/Na and Mg2+/Mg are -3.05, -2.90, -2.71 and -2.37 V respectively. Which one of the following is the strongest oxidising agent ?
1. Mg2+
2. Ba2+
3. Na+
4. Li+
Equivalent conductances of NaCl, HCl and C2H5COONa at infinite dilution are 126.45, 426.16 and 91 . The equivalent conductance of C2H5COOH is :
1. 201.28
2. 390.71
3. 698.28
4. 540.48
The equivalent conductance of M/32 solution of a weak monobasic acid is 8.0 mho cm2 and at infinite dilution is 400 mhocm2. The dissociation constant of the acid is
1. 1.25 x 10-5
2. 1.25 x 10-6
3. 6.25 x 10-4
4. 1.25 x 10-4