When formic acid is heated with concentrated `H_(2)SO_(4)`, the gas evolved is

Options

A. only `CO_(2)`
B. only CO
C. a mixture of `CO and CO_(2)`
D. a mixture of `SO_(2) and CO_(2)`

Explanation

To solve the question "When formic acid is heated with concentrated H₂SO₄, what gas evolves?", we can follow these steps:

### Step 1: Identify the reactants
The reactants in this reaction are formic acid (HCOOH) and concentrated sulfuric acid (H₂SO₄).

**Hint:** Look for the chemical formulas of the substances involved in the reaction.

### Step 2: Understand the reaction
When formic acid is heated with concentrated sulfuric acid, it undergoes dehydration. This means that water is removed from the formic acid, leading to the formation of other products.

**Hint:** Consider what happens to organic acids when they are heated with strong acids.

### Step 3: Write the reaction
The reaction can be represented as follows:
\[ \text{HCOOH} + \text{H}_2\text{SO}_4 \rightarrow \text{CO} + \text{H}_2\text{O} \]

In this reaction, formic acid decomposes to produce carbon monoxide (CO) and water (H₂O).

**Hint:** Focus on the products formed during the reaction and their significance.

### Step 4: Identify the gas evolved
From the reaction, we can see that the gas evolved is carbon monoxide (CO).

**Hint:** Look for the gaseous products in the reaction equation.

### Final Answer
When formic acid is heated with concentrated sulfuric acid, the gas evolved is carbon monoxide (CO).

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