Read the following statements carefully and identify X, Y and Z respectively.
(i) X is stored under kerosene.
(ii) Y catches fire on exposure to air and is stored in water.
(iii) Z does not react with cold or hot water but reacts with steam.

Options

A. Na, Mg, Cu
B. Na, P, Fe
C. Cu, Zn, K
D. Zn, Cu, Na

Explanation

To solve the problem, we need to identify the substances X, Y, and Z based on the given statements:

### Step 1: Identify X
- The first statement says, "X is stored under kerosene."
- Sodium (Na) is a metal that reacts vigorously with water and oxygen, producing a lot of heat. To prevent this reaction, sodium is stored under kerosene.
- Therefore, **X = Sodium (Na)**.

### Step 2: Identify Y
- The second statement says, "Y catches fire on exposure to air and is stored in water."
- Phosphorus (P) is known to ignite when exposed to air, especially the white form of phosphorus. To prevent it from catching fire, phosphorus is stored underwater.
- Therefore, **Y = Phosphorus (P)**.

### Step 3: Identify Z
- The third statement says, "Z does not react with cold or hot water but reacts with steam."
- Iron (Fe) is a less reactive metal that does not react with cold or hot water but does react with steam to form iron oxide and hydrogen gas.
- Therefore, **Z = Iron (Fe)**.

### Summary of Identifications
- **X = Sodium (Na)**
- **Y = Phosphorus (P)**
- **Z = Iron (Fe)**

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