`NH_4 Cl hArr NH_3 + HCl` reaction is called

Options

A. lonic dissociation
B. thermal decomposition
C. thermal dissociation
D. double decomposition

Explanation

To determine the type of reaction represented by the equation \( NH_4Cl \rightleftharpoons NH_3 + HCl \), we can analyze the characteristics of the reaction step by step.

### Step 1: Identify the Reactants and Products
The reactant in this reaction is ammonium chloride (\( NH_4Cl \)), and the products are ammonia (\( NH_3 \)) and hydrochloric acid (\( HCl \)).

**Hint:** Look for the substances involved in the reaction to understand what is being formed and what is being broken down.

### Step 2: Classify the Reaction
We need to classify the reaction into one of the following categories:
1. Ionic Dissociation
2. Thermal Decomposition
3. Thermal Dissociation
4. Double Decomposition

**Hint:** Review the definitions of each type of reaction to see which one fits the given reaction.

### Step 3: Analyze Ionic Dissociation
Ionic dissociation involves the separation of ions in a compound. In this case, \( NH_4Cl \) does not simply dissociate into ions; it produces two distinct molecular products.

**Hint:** Ionic dissociation typically results in ions, not neutral molecules.

### Step 4: Analyze Thermal Decomposition
Thermal decomposition is a process where a single compound breaks down into two or more products when heat is applied. In this case, \( NH_4Cl \) decomposes into \( NH_3 \) and \( HCl \), which indicates that heat is involved in breaking down the compound.

**Hint:** Look for a reaction where one compound breaks down into multiple products, especially under heat.

### Step 5: Analyze Thermal Dissociation
Thermal dissociation refers to the breaking down of a compound into ions or smaller molecules, typically requiring heat. However, in this case, the products are not ions but neutral molecules.

**Hint:** Thermal dissociation usually results in ions, so check if the products are ionic or molecular.

### Step 6: Analyze Double Decomposition
Double decomposition involves two compounds reacting to form two new compounds. However, in this reaction, we only have one reactant decomposing into two products, not two reactants exchanging components.

**Hint:** Double decomposition requires two reactants, so this does not apply here.

### Conclusion
Based on the analysis, the reaction \( NH_4Cl \rightleftharpoons NH_3 + HCl \) is classified as a **thermal decomposition reaction** because one compound (ammonium chloride) decomposes into two distinct products (ammonia and hydrochloric acid) when heat is applied.

**Final Answer:** The reaction is called **thermal decomposition**.