PLZ HELP, Its The Nature of Oxidation and Reduction for chemistry

Oxidation is defined as the chemical process in which substance loses electron and hydrogen or gain oxygen while in the process of reduction, substance gains electron and hydrogen or loses oxygen.

So, from the given equation:

a. It is an oxidation reaction as Rb loses one elctron.

b. It is a reduction reaction as Te gains two electrons and become Te2-

c. It is a reduction reaction as H atom gains electrons.

d. It is an oxidation reaction as P loses 3 electrons.

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