Warming ammonium chloride with sodium hydroxide in a test tube is an example of :

Options

A. closed system
B. isolated system
C. open system
D. None of these

Answer

To solve the question regarding the warming of ammonium chloride with sodium hydroxide in a test tube, we can follow these steps:

### Step 1: Identify the Components
We have two substances involved in the reaction:
- Ammonium chloride (NH4Cl)
- Sodium hydroxide (NaOH)

### Step 2: Understand the Process
When ammonium chloride is warmed with sodium hydroxide, a chemical reaction occurs. This reaction involves the exchange of heat and mass.

### Step 3: Determine the Type of System
In this scenario, we need to determine whether the system is open, closed, or isolated. Since we are warming the substances in a test tube, and the test tube is not sealed, it allows for the exchange of both heat and mass with the surroundings.

### Step 4: Classify the System
Since mass can be transferred (for example, gases can escape), this indicates that the system is an **open system**.

### Step 5: Choose the Correct Option
Based on the classification of the system as an open system, we can now look at the options provided in the question. The correct answer is the one that identifies the process as an open system.

### Final Answer
The warming of ammonium chloride with sodium hydroxide in a test tube is an example of an **open system**.