Chromium is obtained by reducing connentrated chromite ore with :

Options

A. red hot coke
B. gaseous hydrogen
C. aluminium powder
D. carbon monoxide

Explanation

To solve the question of how chromium is obtained by reducing concentrated chromite ore, we can follow these steps:

### Step 1: Identify the ore
Chromium is primarily obtained from chromite ore, which is mainly composed of chromium(III) oxide (Cr2O3).

### Step 2: Understand the reduction process
Reduction is a chemical reaction that involves the gain of electrons or a decrease in oxidation state. In metallurgy, reduction is often used to extract metals from their ores.

### Step 3: Determine the reducing agent
In the context of reducing chromite ore, we need to identify a suitable reducing agent. The options provided are:
- Red hot coke
- Gaseous hydrogen
- Aluminum
- Carbon monoxide

### Step 4: Analyze the options
- **Red hot coke**: Typically used in the reduction of iron ores but not commonly for chromium.
- **Gaseous hydrogen**: Can reduce some metal oxides but is not the preferred method for chromium.
- **Aluminum**: Known for its use in the aluminum reduction process (thermite reaction) for extracting chromium from chromite ore.
- **Carbon monoxide**: Generally used in the reduction of certain metal oxides but not as effective for chromium.

### Step 5: Conclude the correct answer
Based on the analysis, the most effective reducing agent for obtaining chromium from concentrated chromite ore is **aluminum**. The reaction can be summarized as follows:
\[ \text{Cr}_2\text{O}_3 + 2\text{Al} \rightarrow 2\text{Cr} + \text{Al}_2\text{O}_3 \]

### Final Answer
Chromium is obtained by reducing concentrated chromite ore with **aluminum**.

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