Oxidation And Reduction Reactions

Oxidation states of S are: SO₃²⁻: +4, S₂O₄²⁻: +3, S₂O₆²⁻: +5.

Step 1: Reducing agent itself gets oxidised.
Step 2: In option (D), H₂O₂ reduces Ag₂O to Ag.

Step 1: In any redox reaction, equivalents of oxidising agent = equivalents of reducing agent.
Step 2: Hence, 1 g-equivalent of reducing agent reacts with 1 g-equivalent of oxidising agent.

Step 1: Stoichiometry of the reaction.
From the stoichiometry of the reaction, the molar ratio between KMnO and oxalate is 1:2. This means that 1 mole of KMnO reacts with 2 moles of oxalate.

Step 2: Use the molarity and volume.
For 50 mL of 0.02 M KMnO , the equivalent volume of oxalate solution can be calculated as follows: The equivalent moles of oxalate are . Thus, the equivalent volume of oxalate solution is: Thus, the correct answer is (2).

Step 1: Identify oxidation states.
In the reaction, bromine undergoes both reduction (gains electrons) and oxidation (loses electrons). Therefore, bromine is both reduced and oxidised.
Thus, the correct answer is (4).

Step 1: Normality relation:
Step 2:
Step 3: Mass of pure salt required =
Step 4:

Step 1: Oxidising agent gains electrons.
Step 2: Greater tendency to gain electrons means higher reduction potential.
Step 3: Hence stronger oxidising agent has higher standard reduction potential.

Step 1: In (A), H₂O₂ oxidises I⁻ to I₂.
Step 2: In (B), H₂O₂ itself is oxidised to O₂.

The compound given is K₂Cr₂O₇ (potassium dichromate). To determine the oxidation state of chromium (Cr), we need to follow the steps below:
1. Assign Oxidation States: - Potassium (K) has a charge of because it is an alkali metal. - Oxygen (O) generally has an oxidation state of in most compounds, including this one. 2. Set up the equation: - Let the oxidation state of chromium be . - In K₂Cr₂O₇, we have 2 potassium ions ( ), 2 chromium ions ( ), and 7 oxygen atoms ( ). - The total charge on the compound is zero, so the sum of all oxidation states must equal zero: 3. Conclusion: - The oxidation state of chromium in is .