`NH_(3)` and `H_(2)O` form `NH_(4)OH` by

Options

A. electrovalent bond
B. covalent bond
C. coordination bond
D. none of these

Explanation

To solve the question of how NH₃ (ammonia) and H₂O (water) form NH₄OH (ammonium hydroxide), we can follow these steps:

### Step 1: Understand the Reactants
- **NH₃ (Ammonia)**: A basic compound that can accept protons (H⁺).
- **H₂O (Water)**: A neutral molecule that can act as both an acid and a base, depending on the reaction conditions.

### Step 2: Identify the Reaction Type
- The reaction between NH₃ and H₂O is an acid-base reaction. In this case, NH₃ acts as a base, and H₂O acts as an acid.

### Step 3: Proton Transfer
- In this reaction, NH₃ accepts a proton (H⁺) from H₂O.
- This can be represented as:
- NH₃ + H₂O → NH₄⁺ + OH⁻

### Step 4: Formation of NH₄OH
- The NH₄⁺ ion (ammonium ion) combines with the OH⁻ ion (hydroxide ion) to form NH₄OH (ammonium hydroxide).

### Step 5: Determine the Type of Bond
- The bond formed between NH₄⁺ and OH⁻ can be classified as an ionic bond (or electrovalent bond) because it involves the attraction between positively charged ammonium ions and negatively charged hydroxide ions.

### Conclusion
- Therefore, the formation of NH₄OH from NH₃ and H₂O involves the transfer of a proton and results in the formation of an ionic bond.

### Final Answer
- The correct answer is that NH₃ and H₂O form NH₄OH through an **electrovalent bond** (ionic bond).

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