In a typical fuel cell, the reactants(R) and product (P) are:

Options

A. `R = H_2(g), O_2(g), P= H_2O_2(l)`
B. `R = H_2(g), O_2(g), P= H_2O(l)`
C. `R = H_2(g), O_2(g), Cl_2(g), P= HClO_4(aq)`
D. `R = H_2(g), N_2(g), P= NH_3(aq)`

Answer

To solve the question regarding the reactants and products in a typical fuel cell, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Fuel Cells**:
- A fuel cell is an electrochemical device that converts the chemical energy of a fuel (usually hydrogen) and an oxidant (usually oxygen) into electrical energy.

2. **Identifying Reactants**:
- In a typical hydrogen fuel cell, the primary reactants are hydrogen (H₂) and oxygen (O₂). These gases are fed into the fuel cell.

3. **Chemical Reactions in the Fuel Cell**:
- At the anode (the negative electrode), hydrogen undergoes oxidation. This means that hydrogen molecules lose electrons:
\[ 2H_2 \rightarrow 4H^+ + 4e^- \]
- At the cathode (the positive electrode), oxygen undergoes reduction. Oxygen molecules gain electrons and react with protons (H⁺) to form water:
\[ O_2 + 4H^+ + 4e^- \rightarrow 2H_2O \]

4. **Overall Reaction**:
- The overall reaction in a hydrogen fuel cell can be summarized as:
\[ 2H_2 + O_2 \rightarrow 2H_2O \]
- This indicates that two molecules of hydrogen react with one molecule of oxygen to produce two molecules of water.

5. **Identifying Products**:
- The primary product of this reaction is water (H₂O), and heat is also released as a byproduct.

6. **Final Answer**:
- Therefore, in a typical fuel cell, the reactants are hydrogen and oxygen, and the product is water.

### Summary:
- **Reactants**: Hydrogen (H₂) and Oxygen (O₂)
- **Product**: Water (H₂O)