Give the formula for the boiling point elevation constant $(K_b)$.

• A
  $K_b = \frac{R \times M_1 \times T_b^2}{1000 \times \Delta_{vap}H}$
• B
  $K_b = \frac{R \times M_1 \times T_b}{1000 \times \Delta_{vap}H}$
• C
  $K_b = \frac{R \times T_b^2}{1000 \times \Delta_{vap}H}$
• D
  $K_b = \frac{M_1 \times T_b^2}{1000 \times \Delta_{vap}H}$