Question
Question: In the equation \(NO_2^\Theta + {H_2}O \to NO_3^\Theta + 2{H^ \oplus } + n{e^ - }\) n stands for...
In the equation NO2Θ+H2O→NO3Θ+2H⊕+ne− n stands for
1
2
3
4
2
Solution
To find the value of 'n', we need to balance the equation in terms of both atoms and charge.
1. Balancing Atoms:
The atoms (N, O, H) are already balanced on both sides.
2. Balancing Charge:
-
Reactant Side Total Charge:
- Charge of NO2Θ: -1
- Charge of H2O: 0
- Total Reactant Charge = -1 + 0 = -1
-
Product Side Total Charge:
- Charge of NO3Θ: -1
- Charge of 2H⊕: 2 * (+1) = +2
- Charge of ne−: n * (-1) = -n
- Total Product Charge = -1 + 2 - n = 1 - n
For the equation to be balanced, the total charge on the reactant side must be equal to the total charge on the product side.
So, we set up the equation:
Total Reactant Charge = Total Product Charge
−1=1−n
Now, solve for n:
n=1−(−1)
n=1+1
n=2
Alternative Method: Oxidation State Change
We can also determine 'n' by calculating the change in the oxidation state of Nitrogen.
-
Oxidation state of N in NO2Θ: Let the oxidation state of N be x. x+2(−2)=−1 x−4=−1 x=+3
-
Oxidation state of N in NO3Θ: Let the oxidation state of N be y. y+3(−2)=−1 y−6=−1 y=+5
The oxidation state of Nitrogen changes from +3 to +5. This is an increase of 2, meaning Nitrogen loses 2 electrons.
Therefore, n = 2.