(A) : Chlorine is gas, bromine is liquid and iodine is solid
(R) : Intermolecular attraction forces increase upon increase in molecular masses .

Options

A. Both A & R are true, R is the correct explanation of A
B. Both A & R are true, R is not correct explanation of A
C. A is true, R is false
D. A is false, R is true

Answer

To analyze the given statements, we will break down the assertion and reason step by step.

### Step 1: Understanding the Assertion
The assertion states: "Chlorine is a gas, bromine is a liquid, and iodine is a solid."
- This is true as chlorine (Cl2) exists as a gas at room temperature, bromine (Br2) exists as a liquid, and iodine (I2) exists as a solid.

### Step 2: Understanding the Reason
The reason states: "Intermolecular attraction forces increase upon increase in molecular masses."
- This is also true. As we move down the group of halogens (from chlorine to bromine to iodine), the molecular mass increases. Higher molecular masses lead to stronger London dispersion forces (a type of van der Waals force) due to the increased polarizability of the molecules.

### Step 3: Relating Assertion and Reason
- The assertion is about the physical states of chlorine, bromine, and iodine, while the reason explains why these states differ based on intermolecular forces.
- As molecular mass increases (from Cl2 to Br2 to I2), the intermolecular forces also increase, which explains why chlorine is a gas (weak intermolecular forces), bromine is a liquid (intermediate forces), and iodine is a solid (stronger forces).

### Step 4: Conclusion
- Both the assertion and reason are true, and the reason correctly explains the assertion. Therefore, the correct answer is that both the assertion and reason are valid, and the reason is the correct explanation of the assertion.

### Final Answer:
Both the assertion and reason are true, and the reason is the correct explanation for the assertion.

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