Which of the following is redox reaction?

Options

A. `2Na[Ag(CN)_(2)]+Zn to Na_(2)[Zn(CN)_(4)]+2Ag`
B. `BaO_(2)+H_(2)SO_(4) to BaSO_(4)+H_(2)O_(2)`
C. `N_(2)O_(5)+H_(2)O to 2HNO_(3)`
D. `AgNO_(3)+KI to AgI+KNO_(3)`

Answer

To determine which of the given reactions is a redox reaction, we need to analyze the oxidation states of the elements involved in each reaction. A redox reaction involves both oxidation (loss of electrons) and reduction (gain of electrons). Here’s a step-by-step solution:

### Step 1: Identify the reactions
List the reactions provided in the question. For each reaction, we will calculate the oxidation states of the elements involved.

### Step 2: Calculate oxidation states for each element in the first reaction
Assuming the first reaction involves silver (Ag) and cyanide (CN):
- For Ag in AgCN:
- Let the oxidation state of Ag be \( x \).
- The oxidation state of CN is -1 (C is -1 and N is +1).
- The equation becomes: \( x + (-1) = 0 \).
- Solving this gives \( x = +1 \) for Ag.

### Step 3: Determine the change in oxidation state for Ag
- If Ag goes from +1 to 0 (as it is reduced), it indicates that Ag is gaining electrons.

### Step 4: Calculate oxidation states for zinc in the second reaction
Assuming the second reaction involves zinc (Zn):
- For Zn in ZnO:
- Let the oxidation state of Zn be \( y \).
- The oxidation state of O is -2.
- The equation becomes: \( y + (-2) = 0 \).
- Solving this gives \( y = +2 \) for Zn.

### Step 5: Determine the change in oxidation state for Zn
- If Zn goes from 0 to +2 (as it is oxidized), it indicates that Zn is losing electrons.

### Step 6: Analyze the remaining reactions
For the other reactions:
- Check the oxidation states of all elements involved.
- If the oxidation states do not change for any element, then that reaction is not a redox reaction.

### Step 7: Conclusion
Based on the analysis:
- The first reaction (AgCN) is a redox reaction because Ag is reduced (gains electrons).
- The other reactions do not involve any changes in oxidation states, indicating they are not redox reactions.

### Final Answer
The first reaction is a redox reaction.

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