Two substances, A and B were made to react to form a third substance, `A_2 `B according to the following reaction : `2A + B to A_2 B`. Which of the following statements concerning this reaction are incorrect? (i) The product `A_2 `B shows the properties of substances A and B. (ii) The product will always have a fixed composition (iii) The product so formed cannot be classified as a compound. (iv) The product so formed is an element.

Options

A. (i), (ii) and (iii)
B. (ii), (iii) and (iv)
C. (i), (iii) and (iv)
D. (iii) and (iv)

Explanation

To determine which statements concerning the reaction \(2A + B \rightarrow A_2B\) are incorrect, let's analyze each statement step by step.

### Step 1: Analyze the Product
The reaction produces a new substance, \(A_2B\). This substance is a compound formed from the elements A and B.

### Step 2: Evaluate Statement (i)
**Statement (i):** "The product \(A_2B\) shows the properties of substances A and B."

- **Analysis:** Compounds have properties that are different from the properties of the individual elements that compose them. Therefore, the product \(A_2B\) will not show the properties of A and B.
- **Conclusion:** This statement is **incorrect**.

### Step 3: Evaluate Statement (ii)
**Statement (ii):** "The product will always have a fixed composition."

- **Analysis:** By definition, a compound has a fixed composition. In this case, \(A_2B\) will always consist of 2 atoms of A and 1 atom of B, regardless of the amount produced.
- **Conclusion:** This statement is **correct**.

### Step 4: Evaluate Statement (iii)
**Statement (iii):** "The product so formed cannot be classified as a compound."

- **Analysis:** The product \(A_2B\) is formed from the combination of A and B, which classifies it as a compound. Therefore, this statement is incorrect.
- **Conclusion:** This statement is **incorrect**.

### Step 5: Evaluate Statement (iv)
**Statement (iv):** "The product so formed is an element."

- **Analysis:** An element consists of only one type of atom. Since \(A_2B\) contains two different types of atoms (A and B), it cannot be classified as an element.
- **Conclusion:** This statement is **incorrect**.

### Final Conclusion
The incorrect statements are:
1. Statement (i)
2. Statement (iii)
3. Statement (iv)

Thus, the incorrect statements concerning the reaction are (i), (iii), and (iv).