Which one of the following is not an example of a redox reaction?

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Q: 35 (NDA-I/2022)

Which one of the following is not an example of a redox reaction?

question_subject: 

Science

question_exam: 

NDA-I

stats: 

0,15,20,15,7,4,9

keywords: 

{'redox reaction': [0, 0, 0, 2], 'zn cu': [0, 0, 0, 1], 'zns04': [0, 0, 0, 1]}

Option 1, A1C13 + 3H20 -> Al(OH)3 + 3HC1, is not an example of a redox reaction. To determine if a reaction is a redox reaction, we need to compare the oxidation states of the elements involved before and after the reaction.

In a redox reaction, there is a transfer of electrons between reactant species. One species is oxidized (loses electrons) while another is reduced (gains electrons). Looking at option 1, the oxidation states of the elements on both sides of the reaction are:

A1 in A1C13: +3

H in H20: +1

Al in Al(OH)3: +3

H in HC1: +1

We see that the oxidation states remain the same before and after the reaction. Since there is no change in oxidation states, this reaction is not a redox reaction.

Option 2, 2NaH -> 2Na + H2, is an example of a redox reaction. The Na in NaH is oxidized from an oxidation state of -1 to 0 in Na, while the H in NaH is reduced from an oxidation state of +1 to 0 in H2

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