Question

Consider the following \[ \mathrm{HF,\ H_2O,\ BeCl_2,\ CO_2,\ BF_3,\ NF_3,\ CCl_4,\ CHCl_3} \] The number of polar molecules is

• A. \(2\)
• B. \(3\)
• C. \(4\)
• D. \(5\)

Hint:

A molecule is polar if it has \[ \boxed{\text{a non-zero net dipole moment}.} \] Always consider both \[ \boxed{\text{bond polarity and molecular geometry}.} \]

Answer 1

The Correct Option is C

Step 1: Identify the polar molecules. The polar molecules are \[ \mathrm{HF,\ H_2O,\ NF_3,\ CHCl_3.} \]

Step 2: Identify the non-polar molecules. The following molecules are symmetrical, so their bond dipole moments cancel. \[ \mathrm{BeCl_2,\ CO_2,\ BF_3,\ CCl_4.} \] Hence, they are non-polar.

Step 3: Count the polar molecules. Number of polar molecules \[ = 4. \] Hence, \[ \boxed{4}. \] Thus, \[ \boxed{(C)} \] is the correct answer.