Manganese react with very dilute `HNO_(3)` to evolve ………gas.

Options

A. `H_(2) `
B. `N_(2)`
C. `O_(2)`
D. `NO_(2)`

Explanation

To solve the question regarding the reaction of manganese with very dilute HNO₃, we can follow these steps:

### Step 1: Understand the Reactants
Manganese (Mn) is a transition metal that can react with acids. In this case, we are dealing with very dilute nitric acid (HNO₃).

**Hint:** Identify the nature of the reactants and their states (solid, liquid, gas).

### Step 2: Determine the Reaction Type
When manganese reacts with dilute nitric acid, it is important to note that nitric acid can act as both an acid and an oxidizing agent.

**Hint:** Consider the properties of nitric acid and how it interacts with metals.

### Step 3: Write the Reaction
The general reaction of manganese with dilute nitric acid can be represented as:
\[ \text{Mn} + 2 \text{HNO}_3 \rightarrow \text{Mn(NO}_3\text{)}_2 + \text{H}_2 \]

In this reaction, manganese reacts with nitric acid to form manganese nitrate and hydrogen gas is evolved.

**Hint:** Look for the products formed in the reaction and identify any gases released.

### Step 4: Identify the Gas Evolved
From the reaction, we see that hydrogen gas (H₂) is produced.

**Hint:** Recall common gases produced in reactions involving metals and acids.

### Step 5: Conclusion
The gas evolved when manganese reacts with very dilute HNO₃ is hydrogen gas (H₂).

**Final Answer:** The correct answer is option 1, H₂.