(a) compute the voltage at 25°c of an electrochemical cell consisting of pure lead immersed in a 5 × 10−2 m solution of pb2+ ions and pure tin in a 0.25 m solution of sn2+ ions. (b) write the spontaneous electrochemical reaction.

a) The cell potential energy is -0.01 V

b) The spontaneous chemical reaction -

Explanation:

The chemical reaction between lead and tin ions is follows.

The cell potential can be calculated by using Nernst equation.

Substitute the  values.

Therefore, the cell potential is 0.01V.

b)

The voltage value is negative.The spontaneous eectrochemical reaction is reverse of the electrochemical reaction in part(a)

Therefore, spontaneous reaction is as follows.

14,16 18 reacts with group

  the   balanced   equation   for   reaction of   ca metal   with   o2 to   produce   cao   is as below

2 ca+ o2→ 2 cao2

  explanation

the reaction is   balanced     since the   number of atoms   in reactant side is   equal to   number of atoms   in   product side.   for   example   they   are 2   atom of   ca in   reactant   side   and   2   atoms of ca   in   the product side.

  the   process   is a   meet the   requirement   of   redox   reaction because :     calcium   is   oxidized   from   oxidation state 0   to 2+   while   oxygen   is reduced from   oxidation   state   0   to 2-