To determine how many of the given statements are correct, we will analyze each statement step by step.
### Step 1: Analyze the first statement
**Statement:** "Valency of an element is always a whole number."
**Explanation:**
- Valency refers to the combining capacity of an element, which is determined by the number of electrons an atom can donate, accept, or share during a chemical reaction.
- Electrons are discrete particles and can only be transferred in whole numbers (1, 2, 3, etc.). For example, an atom can lose one electron to become positively charged or gain one electron to become negatively charged, but it cannot lose or gain half an electron.
- Therefore, the valency of an element, which is based on the number of electrons involved in bonding, must also be a whole number.
**Conclusion:** This statement is **true**.
### Step 2: Analyze the second statement
**Statement:** "`2H₂S + SO₂ → 3S + 2H₂O` is a disproportionation reaction."
**Explanation:**
- A disproportionation reaction is a specific type of redox reaction where a single substance is both oxidized and reduced, resulting in two different products with different oxidation states.
- In the reaction given, we need to determine the oxidation states of sulfur in the reactants and products:
- In H₂S (hydrogen sulfide), sulfur has an oxidation state of -2.
- In SO₂ (sulfur dioxide), sulfur has an oxidation state of +4.
- In the products, sulfur (S) is elemental, which has an oxidation state of 0.
- Here, sulfur in H₂S is oxidized from -2 to 0, and sulfur in SO₂ is reduced from +4 to 0.
- Since the same element (sulfur) undergoes both oxidation and reduction, this reaction qualifies as a disproportionation reaction.
**Conclusion:** This statement is **true**.
### Final Conclusion:
Both statements are correct. Therefore, the answer is that **2 statements are correct**.
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