Question

Given the redox reaction: Ni + Sn4+ → Ni2+ + Sn2+

Answer 1

 1. Na 
2. Ni 
3. Na2S 
4. Electrolytic Cell (Galvanic and Voltaic are synonyms, both are electric cells without an external power source. 
5. 3 
6. The first one 
7. Na 
8. Reducing agents are oxidized 
hope this helps you

Answer 2

Answer: Ni

Explanation: Oxidation-reduction reaction or redox reaction is defined as the reaction in which oxidation and reduction reactions occur simultaneously.

Oxidation reaction is defined as the reaction in which a substance looses its electrons. The oxidation state of the substance increases.

$Ni\rightarrow Ni^{2+}+2e^-$

Reduction reaction is defined as the reaction in which a substance gains electrons. The oxidation state of the substance gets reduced.

$Sn^{4+}+2e^-\rightarrow Sn^{2+}$

The oxidation state of nickel increases from 0 to +2, it is getting oxidized and it undergoes oxidation reaction.