The catalyst used in the water-gas shift reaction is

Options

A. Sodium arsenite
B. Nickel
C. Potassium permanganate
D. Iron chromate

Answer

To solve the question regarding the catalyst used in the water-gas shift reaction, we can follow these steps:

### Step 1: Understand the Water-Gas Shift Reaction
The water-gas shift reaction is a chemical reaction that converts carbon monoxide (CO) and water (H2O) into carbon dioxide (CO2) and hydrogen gas (H2). This reaction is important in the industrial production of hydrogen.

### Step 2: Identify the Catalyst
In the water-gas shift reaction, a catalyst is used to enhance the reaction rate without being consumed in the process. The common catalysts used in this reaction are metal oxides.

### Step 3: Analyze the Given Options
The options provided in the question are:
1. Sodium arsenate
2. Nickel
3. Potassium permanganate
4. Iron chromate

### Step 4: Match the Catalyst with the Reaction
From the knowledge of the water-gas shift reaction, it is known that iron oxide (Fe2O3) and chromium oxide (Cr2O3) are commonly used as catalysts. Therefore, the correct choice from the given options that corresponds to the catalyst used in the water-gas shift reaction is:

**Iron Chromate (Option 4)**

### Final Answer
The catalyst used in the water-gas shift reaction is **Iron Chromate (FeCr2O4)**.

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