Assertion (A) : Dipole moment of  ${\text{NH}}_3>{\text{NF}}_{\text{3}}$
Reason : In  ${\text{NH}}_3$ molecule, the orbital dipole due to lone pair is in the same direction as the resultant dipole moment of the three N – H bonds whereas in  ${\text{NF}}_{\text{3}}$ molecule, the orbital dipole due to lone pair is in the direction opposite to the resultant dipole moment of the three N – F bonds