`CN^(Theta),SCN^(Theta)` and `N_(3)^(Theta)` are called ………….

Answer

To solve the question regarding the classification of CN⁻, SCN⁻, and N₃⁻, we can follow these steps:

### Step 1: Identify the Compounds
The compounds given in the question are:
- CN⁻ (Cyanide ion)
- SCN⁻ (Thiocyanate ion)
- N₃⁻ (Azide ion)

### Step 2: Understand Their Nature
These ions are not halides (which are typically F⁻, Cl⁻, Br⁻, and I⁻). Instead, they are ions that have characteristics similar to halides in terms of their charge and reactivity.

### Step 3: Define Pseudohalides
Pseudohalides are defined as ions or compounds that resemble halides but do not contain halogen atoms. They exhibit similar chemical behavior to halides, particularly in their ability to form salts and participate in similar types of reactions.

### Step 4: Conclude the Classification
Since CN⁻, SCN⁻, and N₃⁻ do not contain halogens but behave similarly to halide ions, they are classified as pseudohalides.

### Final Answer
CN⁻, SCN⁻, and N₃⁻ are called **pseudohalides**.

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