Which ion can be both an oxidizing agent and reducing agent? A)Sn2+

B)Cu2+

C)Al3+

D)Fe3+

a)  Sn 2+  

Explanation:A reducing agent is a substance  that can be oxidized when it loses electrons while An oxidizing agent is a substance that is reduced when it gains   electrons.

 Considering  Cu 2+,   Fe 3+, Al 3+, Here,  Cu 2+ can  be reduce to its Copper metal, same for  Al 3+ to Aluminium  metal  and Fe 3+  to Fe 2+ ion  and will not be oxidized further since they are in their most oxidized states. The three ions are acting as only oxidizing agents.

while Sn 2+ can be oxidized to become Sn 4+ and also  be reduced to become Sn metal  acting as a reducing agent and an oxidizing agent.

idk

explanation:

  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-