Fill in the blanks with the most appropriate option.
'W' is a very reactive metal, reacts vigorously with oxygen and water therefore, stored in `ul(" (1) ")`.
'X' is a non-metal, soft and dull and forms `ul(" (2) ")` oxides with oxygen.
'Y' is very reactive `ul(" (3) ")`, catches fire if exposed to air, therefore, stored in water. 'Z' does not react with dilute hydrochloric acid even on heating but it reacts with sulphuric acid. When it is exposed to moist air for long, it acquires a dull `ul(" (4) ")` coating.

Options

A. 1-Water, 2-basic, 3-metal, 4-reddish brown
B. 1-Kerosene, 2-acidic, 3-metal, 4-reddish brown
C. 1-Kerosene, 2-acidic, 3-non-metal, 4-green
D. 1-Water, 2-basic, 3-non-metal, 4-green

Answer

To solve the question, we need to fill in the blanks with the most appropriate options based on the given clues about metals and non-metals.

### Step-by-Step Solution:

1. **Identifying 'W':**
- The question states that 'W' is a very reactive metal that reacts vigorously with oxygen and water.
- The most common metal that fits this description is **Sodium (Na)**.
- Sodium is stored in **kerosene** to prevent it from reacting with moisture and oxygen in the air.
- **Answer for (1): Kerosene**

2. **Identifying 'X':**
- 'X' is described as a non-metal that is soft and dull and forms **acidic oxides** with oxygen.
- The non-metal that fits this description is **Sulfur (S)**, which forms sulfur dioxide (SO2) when it reacts with oxygen.
- **Answer for (2): Acidic**

3. **Identifying 'Y':**
- 'Y' is a very reactive substance that catches fire if exposed to air and is stored in water.
- The metal that meets this criterion is **Potassium (K)**, which is more reactive than sodium and must be stored in water to prevent it from igniting in air.
- **Answer for (3): Metal**

4. **Identifying 'Z':**
- 'Z' does not react with dilute hydrochloric acid even on heating but reacts with sulfuric acid. It also acquires a dull coating when exposed to moist air.
- The metal that fits this description is **Iron (Fe)**. Iron does not react with dilute hydrochloric acid but does react with sulfuric acid, and it forms rust (hydrated ferric oxide) when exposed to moisture.
- The dull coating formed is **rust**, which is reddish-brown in color.
- **Answer for (4): Reddish-brown**

### Final Answers:
1. Kerosene
2. Acidic
3. Metal
4. Reddish-brown