A metallic carbide on treatment with water gives a colouless gas which burns readily in air and gives a precipitate with ammonical silver nitrate. The gas is

Options

A. `CH_(4)`
B. `C_(2)H_(6)`
C. `C_(2)H_(4)`
D. `C_(2)H_(2)`

Answer

To solve the question step by step, we will analyze the information given and derive the answer logically.

### Step 1: Identify the reaction of metallic carbide with water
A metallic carbide reacts with water to produce a gas. The question specifies that this gas is colorless and burns readily in air.

**Hint:** Consider common metallic carbides and their reactions with water.

### Step 2: Determine the type of gas produced
The most common metallic carbide that reacts with water is calcium carbide (CaC2). The reaction of calcium carbide with water can be represented as follows:

\[ \text{CaC}_2 + 2 \text{H}_2\text{O} \rightarrow \text{Ca(OH)}_2 + \text{C}_2\text{H}_2 \]

Here, calcium hydroxide (Ca(OH)₂) is formed along with acetylene gas (C₂H₂).

**Hint:** Look for a gas that is produced from a metallic carbide and is known to be colorless and flammable.

### Step 3: Analyze the properties of the gas
The gas produced, acetylene (C₂H₂), is indeed colorless and burns readily in air. This matches the description given in the question.

**Hint:** Recall the properties of acetylene and its behavior when burned.

### Step 4: Check the reaction with ammonical silver nitrate
The question states that the gas gives a precipitate with ammonical silver nitrate. When acetylene reacts with ammonical silver nitrate (AgNO₃ in the presence of NH₄Cl), it forms a white precipitate of silver acetylide (C₂Ag₂).

The reaction can be summarized as:

\[ \text{C}_2\text{H}_2 + 2 \text{AgNO}_3 \rightarrow \text{C}_2\text{Ag}_2 + 2 \text{HNO}_3 \]

The white precipitate confirms the presence of acetylene.

**Hint:** Consider the reactions of alkynes with silver nitrate, specifically how they form precipitates.

### Conclusion
Based on the analysis, the colorless gas produced from the reaction of a metallic carbide with water, which burns readily in air and forms a precipitate with ammonical silver nitrate, is acetylene (C₂H₂).

**Final Answer:** The gas is acetylene (C₂H₂).