question_answer 1)

In the reactions given below, identify the species undergoing oxidation and reduction : (i) \[{{H}_{2}}S(g)+C{{l}_{2}}(g)\to 2HCl(g)+S(s)\] (ii)\[3F{{e}_{3}}{{O}_{4}}(s)+8Al(s)\to 9Fe(s)+4A{{l}_{2}}{{O}_{3}}(s)\] (iii) \[2Na(s)+{{H}_{2}}(g)\to 2NaH(s)\]

Answer:

(i) \[{{H}_{2}}S\] is oxidised to sulphur due to removal of hydrogen. Chlorine (\[C{{l}_{2}}\]) is reduced to \[HCl\] due to combination with hydrogen. (ii) Aluminium is oxidised due to combination with oxygen while \[F{{e}_{3}}{{O}_{4}}\] is reduced due to removal of oxygen from it. (iii) In this reaction sodium is oxidised while hydrogen is reduced. One electron is transferred from sodium to hydrogen.