Prefix 'Alkali' denotes for:-

Options

A. Silvery lustre of IA group
B. Metallic nature of IIA group
C. Active metals of IA group
D. Ashes of plants for IA group

Answer

To answer the question "Prefix 'Alkali' denotes for:", we will analyze the options provided and determine which one correctly relates to the properties associated with alkali substances.

### Step-by-Step Solution:

1. **Understanding the Term 'Alkali':**
- The term 'alkali' refers to a group of basic (alkaline) substances that are derived from alkali metals (Group 1 elements) and some alkaline earth metals (Group 2 elements).

2. **Identifying Key Properties of Alkalis:**
- Alkalis are known for their ability to turn litmus paper blue, indicating a basic nature.
- They possess neutralizing properties, meaning they can neutralize acids.
- They are often caustic or corrosive in nature, which is a characteristic of many alkali substances.

3. **Analyzing the Given Options:**
- **Option A:** Silver – This does not relate to the properties of alkalis.
- **Option B:** Luster of 1st A group – While alkali metals have a shiny luster, this does not define the term 'alkali'.
- **Option C:** Metallic nature of 2nd A group – This describes alkaline earth metals but does not relate to the alkali definition.
- **Option D:** Active metals of 1st A group – This option is relevant as it refers to alkali metals, which are known for their reactivity and basic properties.

4. **Conclusion:**
- The prefix 'alkali' denotes the 'active metals of 1st A group', which are the alkali metals. Therefore, the correct answer is Option D.

### Final Answer:
The prefix 'Alkali' denotes for **active metals of 1st A group**.

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