When `Fe_(S)` is dissovled in aqueous hydrochloric acid in a closed vessel the work done is __________

Explanation

To determine the work done when solid iron (Fe) is dissolved in aqueous hydrochloric acid (HCl) in a closed vessel, we can follow these steps:

### Step 1: Write the chemical reaction.
When iron reacts with hydrochloric acid, the reaction can be represented as:
\[ \text{Fe}_{(s)} + 2\text{HCl}_{(aq)} \rightarrow \text{FeCl}_2_{(aq)} + \text{H}_2_{(g)} \]

### Step 2: Understand the conditions of the reaction.
The reaction is taking place in a closed vessel. This means that no gas can escape or enter the system, and the volume of the system remains constant.

### Step 3: Determine the work done formula.
In thermodynamics, the work done (W) in a system can be expressed as:
\[ W = -P \Delta V \]
where \( P \) is the pressure and \( \Delta V \) is the change in volume.

### Step 4: Analyze the change in volume (\( \Delta V \)).
Since the reaction is occurring in a closed vessel, the volume of the system does not change. Therefore:
\[ \Delta V = 0 \]

### Step 5: Calculate the work done.
Substituting \( \Delta V = 0 \) into the work done formula:
\[ W = -P \cdot 0 = 0 \]

### Conclusion:
Thus, the work done when solid iron is dissolved in aqueous hydrochloric acid in a closed vessel is:
\[ \text{Work done} = 0 \]