In which of the following set-ups reaction will take place?
(i) Magnesium ribbon in copper sulphate solution
(ii) A few pieces of calcium in magnesium sulphate solution
(iii) Copper wire in zinc sulphate solution
(iv) Tron nails in magnesium sulphate solution

Options

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

Explanation

To determine in which of the given setups a reaction will take place, we need to refer to the reactivity series of metals. The reactivity series helps us understand which metals can displace others in a chemical reaction.

### Step-by-Step Solution:

1. **Identify the Reactivity Series**:
The reactivity series from most reactive to least reactive is as follows:
- Potassium (K)
- Sodium (Na)
- Calcium (Ca)
- Magnesium (Mg)
- Aluminum (Al)
- Zinc (Zn)
- Iron (Fe)
- Lead (Pb)
- Hydrogen (H)
- Copper (Cu)
- Mercury (Hg)
- Silver (Ag)
- Gold (Au)

2. **Analyze Each Setup**:
- **(i) Magnesium ribbon in copper sulfate solution**:
- Magnesium is more reactive than copper. Therefore, magnesium will displace copper from copper sulfate.
- **Reaction occurs**.

- **(ii) A few pieces of calcium in magnesium sulfate solution**:
- Calcium is more reactive than magnesium. Therefore, calcium will displace magnesium from magnesium sulfate.
- **Reaction occurs**.

- **(iii) Copper wire in zinc sulfate solution**:
- Copper is less reactive than zinc. Therefore, copper cannot displace zinc from zinc sulfate.
- **No reaction occurs**.

- **(iv) Iron nails in magnesium sulfate solution**:
- Iron is less reactive than magnesium. Therefore, iron cannot displace magnesium from magnesium sulfate.
- **No reaction occurs**.

3. **Conclusion**:
The setups where reactions will take place are:
- (i) Magnesium ribbon in copper sulfate solution
- (ii) A few pieces of calcium in magnesium sulfate solution

### Final Answer:
The reactions will take place in setups (i) and (ii).

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