Select the incorrect statement(s):

Options

A. Magnesium can be burnt in the atmosphere of `CO_(2) and SO_(2)`
B. Magnesium reacts with alkyl halides to form Grignard's reagent
C. Out of Mg and Ca, only Mg reacts with `N_(2)` to form magnesium nitride
D. Calcium is less reactive than magnesium

Answer

To solve the question of identifying the incorrect statements regarding the properties of magnesium and calcium, we will analyze each statement step by step.

### Step 1: Analyze the First Statement
**Statement:** Magnesium can be burnt in the atmosphere of CO2 and SO2.

**Analysis:** This statement is correct. Magnesium reacts with carbon dioxide (CO2) to produce magnesium oxide (MgO) and carbon (C). Similarly, it can react with sulfur dioxide (SO2). Thus, this statement is not incorrect.

### Step 2: Analyze the Second Statement
**Statement:** Magnesium reacts easily with alkyl halides to form Grignard's reagent.

**Analysis:** This statement is also correct. Magnesium reacts with alkyl halides to form Grignard's reagent (R-MgX), which is a significant reagent in organic synthesis. Therefore, this statement is not incorrect.

### Step 3: Analyze the Third Statement
**Statement:** Out of Magnesium and Calcium, only Magnesium reacts with N2 to form Magnesium Nitride.

**Analysis:** This statement is incorrect. Both magnesium and calcium can react with nitrogen (N2) to form their respective nitrides: magnesium nitride (Mg3N2) and calcium nitride (Ca3N2). Therefore, this statement is indeed incorrect.

### Step 4: Analyze the Fourth Statement
**Statement:** Calcium is less reactive than Magnesium.

**Analysis:** This statement is also incorrect. Calcium is actually more reactive than magnesium. As we move down the group in the periodic table, the reactivity of alkaline earth metals increases. Therefore, this statement is incorrect.

### Conclusion
The incorrect statements are:
- Statement 3: "Out of Magnesium and Calcium, only Magnesium reacts with N2 to form Magnesium Nitride."
- Statement 4: "Calcium is less reactive than Magnesium."

### Final Answer
The incorrect statements are statements 3 and 4.

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