Identify the compounds which are reduced and oxidised in the following reaction:
`3N_(2)H_(4)+2BrO_(3)^(-)rarr3N_(2)+2Br^(-)+6H_(2)O`

Options

A. `N_(2)H_(4)` is oxidised and `BrO_(3)^(-)` is reduced.
B. `BrO_(3)^(-)` is oxidised and `N_(2)H_(3)` is reduced.
C. `BrO_(3)^(-)` is both reduced and oxidised.
D. This is not a redox reaction.

Explanation

To identify the compounds that are reduced and oxidized in the given reaction, we will follow these steps:

### Step 1: Write the Reaction
The reaction given is:
\[ 3N_2H_4 + 2BrO_3^- \rightarrow 3N_2 + 2Br^- + 6H_2O \]

### Step 2: Identify the Oxidation States
We need to determine the oxidation states of the relevant elements in the reactants and products.

#### For Nitrogen in Hydrazine (N2H4):
1. In \( N_2H_4 \), let the oxidation state of nitrogen be \( x \).
2. The equation for the oxidation state is:
\[ 2x + 4(-1) = 0 \quad \text{(since H has an oxidation state of -1)} \]
\[ 2x - 4 = 0 \implies 2x = 4 \implies x = +2 \]
Therefore, the oxidation state of nitrogen in \( N_2H_4 \) is +2.

3. In \( N_2 \), the oxidation state of nitrogen is 0.

#### For Bromine in Bromate (BrO3^-):
1. Let the oxidation state of bromine be \( y \).
2. The equation for the oxidation state is:
\[ y + 3(-2) = -1 \quad \text{(since O has an oxidation state of -2)} \]
\[ y - 6 = -1 \implies y = +5 \]
Therefore, the oxidation state of bromine in \( BrO_3^- \) is +5.

3. In \( Br^- \), the oxidation state of bromine is -1.

### Step 3: Determine Changes in Oxidation States
- **For Nitrogen**:
- Changes from +2 in \( N_2H_4 \) to 0 in \( N_2 \).
- This indicates that nitrogen is losing electrons (oxidation).

- **For Bromine**:
- Changes from +5 in \( BrO_3^- \) to -1 in \( Br^- \).
- This indicates that bromine is gaining electrons (reduction).

### Step 4: Conclusion
- **Oxidized Compound**: \( N_2H_4 \) (Nitrogen is oxidized)
- **Reduced Compound**: \( BrO_3^- \) (Bromine is reduced)

Thus, in the reaction:
- \( N_2H_4 \) is oxidized.
- \( BrO_3^- \) is reduced.

### Final Answer
- **Oxidized**: \( N_2H_4 \)
- **Reduced**: \( BrO_3^- \)

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