Electrochemistry

One half cell in a voltaic cell is constructed by dipping silver rod in AgNO3 solution of unknown concentration, other half cell is Zn rod dipped in 1 molar solution of ZnSO4. A voltage of 1.60 V is measured at 298 K for this cell. What is the concentration of Ag+ ions used in terms of log x (x = [Ag+])? E Zn2+/Zn = −0.76 V, E Ag+/Ag = +0.80 V, 2.303RTF = 0.059 V

1. 23.9
2. 45.9
3. 2.92
4. 5.94

In the given electrochemical cell, Ag(s)|AgCl(s)|FeCl2(aq), FeCl3(aq) | Pt(s) at 298 K, the cell potential ( Ecell) will increase when : Choose the correct answer from the options given below :

1. C, D and E Only
2. A and B Only
3. B Only
4. A and E Only

For a Mg | Mg2+(aq) || Ag+(aq) | Ag the correct Nernst Equation is :

1. Ecell = E cell - RT2F [Ag+]2[Mg2+]
2. Ecell = E cell - RT2F [Mg2+][Ag+]
3. Ecell = E cell - RT2F [Ag+][Mg2+]
4. Ecell = E cell + RT2F [Ag+]2[Mg2+]

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

What pressure (bar) of H2 would be required to make emf of hydrogen electrode zero in pure water at 25 ?

1. 0.5
2. 10-14
3. 1
4. 10-7