Which Reactions Are Redox?

In summary, the question is asking to determine which of the four given reactions are redox reactions. The key to identifying a redox reaction is to look for changes in oxidation numbers. After analyzing the reactions, it is concluded that only reactions 1, 2, and 3 are redox reactions, while reaction 4 does not involve any changes in oxidation numbers and therefore is not a redox reaction. It is important to note the oxidation numbers of the elements involved before and after the reaction to accurately determine if it is a redox reaction.
  • #1
terryds
392
13

Homework Statement



Determine which is/are redox reaction/s ?
##1. 2HNO_2 + 2HBr \rightarrow 2NO + BR_2 + 2H_2O##
##2. PbO_2 + SO_2 \rightarrow PbO + SO_3##
##3. 2Ag + Cl_2 \rightarrow 2AgCl##
##4. SO_2 + NaOH \rightarrow NaHSO_3##

Homework Equations


Redox reactions are the ones which involves changes in oxidation numbers

The Attempt at a Solution



Since all reactions involves change in oxidation number
1. Br
2. Pb
3. Cl
4. S

I think all the reactions are redox.
But, the answer is just reaction 1, 2, and 3

Please tell me why reaction 4 is not redox reaction
 
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  • #2
What is the oxidation number of S before the reaction? After the reaction?
 
  • #3
Borek said:
What is the oxidation number of S before the reaction? After the reaction?

Hmm... it's +4 and +4... No change... Thankss... I missed it
 

FAQ: Which Reactions Are Redox?

What is a redox reaction?

A redox reaction is a type of chemical reaction in which there is a transfer of electrons between two or more substances. One substance gains electrons (reduction) while the other loses electrons (oxidation).

How can I tell if a reaction is redox?

You can determine if a reaction is redox by looking at the oxidation numbers of the elements involved. If the oxidation numbers change, then it is a redox reaction. You can also look for the presence of a reducing agent and an oxidizing agent, which are substances that facilitate the transfer of electrons in a redox reaction.

What are some examples of redox reactions?

Some common examples of redox reactions include combustion, corrosion, and the reaction between an acid and a metal. In combustion, a substance combines with oxygen to produce heat and light, while in corrosion, a metal loses electrons to oxygen in the air. When an acid reacts with a metal, the metal loses electrons to form a positively charged ion, while the acid gains electrons to form a negatively charged ion.

What is the purpose of balancing redox reactions?

The purpose of balancing redox reactions is to ensure that the number of electrons lost by the reducing agent is equal to the number of electrons gained by the oxidizing agent. This maintains the overall charge balance in the reaction and allows for accurate calculations of the reactants and products.

Are all chemical reactions redox reactions?

No, not all chemical reactions are redox reactions. Some reactions involve only physical changes, such as changes in state (solid, liquid, gas) or changes in concentration. Redox reactions, on the other hand, involve a transfer of electrons between substances.

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