Question

A galvanic (voltaic) cell consists of an electrode composed of nickel in a 1.0 M nickel(II) ion solution and another electrode composed of gold in a 1.0 M gold(III) ion solution, connected by a salt bridge. Calculate the standard potential for this cell at 25 °C.

____V

2)Consider these two entries from a fictional table of standard reduction potentials.

X2+ + 2e- => X(s) E=2.26 V
Y2+ + 2e- => Y(s) E=0.14 V

Which pair of species would react under standard conditions?

_X2+ and Y
_X2+ and Y2+
_X and Y
_X and Y2+

Answer 1

According to the Electrochemical series:

The electrochemical series is arranged in the order of their standard electrode potentials (redox potentials). The most negative E° values are placed at the top of the electrochemical series, and the most positive at the bottom.

The above one in the Electrochemical series displaces the below one of the series. That means above one oxidises and the below one reduces (Deposits on the electrode).

According to the question

X²⁺ + 2e- ------> X(s) E=2.26 V
Y²⁺ + 2e- -------> Y(s) E=0.14 V   

In this case Y2+ to Y, The reduction potential is low, That means it oxidises

Y -------> Y²⁺

and other one become reduced (deposits).

X²⁺ ------> X

Hence under standard conditions X and Y²⁺ takes place.