Which of the following statements is (are) correct ?

Options

A. Antimony on reaction with conc. `HNO_(3)` gives antimonic acid.
B. Maganese on reaction with cold and dilute `HNO_(3)` gives `NO_(2)` gas.
C. `HNO_(2)` disproportionate to give `HNO_(3)` and `NO`
D. `HNO_(3)` on reaction with `P_(4)O_(10)`gives `N_(2)O_(5)`

Explanation

To solve the question regarding which statements are correct, we will analyze each statement one by one based on chemical reactions and properties.

### Step 1: Analyze the first statement
**Statement:** Antimony on reaction with concentrated HNO3 gives antimonic acid.

**Analysis:**
Antimony (Sb) reacts with concentrated nitric acid (HNO3) to produce antimony oxide (Sb4O10), nitrogen dioxide (NO2), and water (H2O). The reaction does not yield antimonic acid (H3SbO4). Therefore, this statement is **incorrect**.

### Step 2: Analyze the second statement
**Statement:** Manganese on reaction with cold and dilute HNO3 gives NO2 gas.

**Analysis:**
The statement is misleading because it refers to manganese (Mn) but seems to confuse it with magnesium (Mg). Manganese does react with cold and dilute HNO3 to produce manganese nitrate (Mn(NO3)2) and hydrogen gas (H2), not NO2. Hence, this statement is also **incorrect**.

### Step 3: Analyze the third statement
**Statement:** HNO2 disproportionates to give HNO3 and NO.

**Analysis:**
Nitrous acid (HNO2) does undergo disproportionation. The reaction can be represented as:
\[ 3HNO2 \rightarrow HNO3 + 2NO + H2O \]
This confirms that HNO2 can produce both nitric acid (HNO3) and nitrogen monoxide (NO). Therefore, this statement is **correct**.

### Step 4: Analyze the fourth statement
**Statement:** HNO3 on reaction with P4O10 gives N2O5.

**Analysis:**
When nitric acid (HNO3) reacts with phosphorus pentoxide (P4O10), it produces dinitrogen pentoxide (N2O5) and phosphoric acid (H3PO4). The reaction can be represented as:
\[ 4HNO3 + P4O10 \rightarrow 4N2O5 + H3PO4 \]
This confirms that the statement is **correct**.

### Conclusion
Based on the analysis:
- The first statement is incorrect.
- The second statement is incorrect.
- The third statement is correct.
- The fourth statement is correct.

Thus, the correct statements are the third and fourth ones.

### Final Answer:
The correct statements are: **C and D**.

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