Prefix 'alkali' for alkali metals denotes:

Options

A. Silvery lutre
B. Metallic nature
C. Active metlas
D. Ashes of plants

Explanation

To solve the question regarding the prefix 'alkali' for alkali metals, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Term 'Alkali':**
- The term 'alkali' is derived from the Arabic word "al-qaly," which refers to the ashes of plants. This indicates a historical connection to the natural sources of these substances.

2. **Identifying the Meaning:**
- The word 'alkali' specifically refers to the presence of certain compounds, particularly the carbonates of alkali metals, which were historically obtained from the ashes of plants.

3. **Relating to Alkali Metals:**
- Alkali metals (Group 1 elements) such as lithium, sodium, and potassium form alkaline hydroxides when reacting with water. The carbonates of these metals are also found in the ashes of plants, which is why they are associated with the term 'alkali.'

4. **Evaluating the Options:**
- Now, let's look at the options provided in the question:
- a) Silvery luster
- b) Metallic nature
- c) Active metals
- d) Access of plants
- Among these options, the one that correctly relates to the origin of the term 'alkali' is option (d) 'Access of plants'.

5. **Conclusion:**
- Therefore, the prefix 'alkali' for alkali metals denotes the 'access of plants', referring to the historical context of how these substances were derived from plant ashes.

### Final Answer:
The prefix 'alkali' for alkali metals denotes 'access of plants'.

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