Nitrogen reacts with calcium and carbon or when `N_2` gas is passed over heated calcium carbide (at `1070 K`) it gives___ which is an important fertiliser marketed under the name Nitrolium.

Options

A. Calcium nitrate
B. Calcium cyanide
C. Calcium cyanamide
D. Calcium nitride

Explanation

To solve the question regarding the reaction of nitrogen with calcium and carbon, or the passing of nitrogen gas over heated calcium carbide, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Reactants**:
- The reactants in the reaction are nitrogen gas (N₂), calcium (Ca), and carbon (C).

2. **Understand the Reaction Conditions**:
- The reaction occurs when nitrogen gas is passed over heated calcium carbide (CaC₂) at a temperature of 1070 K.

3. **Write the Chemical Reaction**:
- When nitrogen reacts with calcium and carbon, or when nitrogen gas is passed over calcium carbide, the primary product formed is calcium cyanamide (CaCN₂).
- The reactions can be represented as:
- \( N_2 + Ca + C \rightarrow CaCN_2 \)
- \( N_2 + CaC_2 \rightarrow CaCN_2 + C \)

4. **Identify the Product**:
- The product formed from these reactions is calcium cyanamide, which is also known as Nitrolium.

5. **State the Importance of the Product**:
- Calcium cyanamide (Nitrolium) is an important fertilizer used in agriculture. It serves various purposes including being a fertilizer, herbicide, and pesticide.

6. **Conclude the Answer**:
- Therefore, the answer to the question is calcium cyanamide (CaCN₂), which is marketed under the name Nitrolium.

### Final Answer:
The product formed is **calcium cyanamide (CaCN₂)**, which is marketed as Nitrolium.

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