The correct order regarding dipole moment is :CH3Cl < CH3FH2O > H2O2 > BF3 > NH3

To determine the correct order of dipole moment, we need to consider the polarity of the molecules. The dipole moment is a measure of the separation of positive and negative charges within a molecule.

1. CH3Cl: This molecule has a polar covalent bond between carbon and chlorine. Chlorine is more electronegative than carbon, causing a partial negative charge on chlorine and a partial positive charge on carbon. The dipole moment of CH3Cl is relatively low compared to the other molecules in the list.

2. CH3FH2O: This molecule contains both polar covalent bonds and hydrogen bonds. The fluorine and oxygen atoms are highly electronegative, resulting in a significant dipole moment. Additionally, the hydrogen bonding in water further increases its dipole moment.

3. H2O2: Hydrogen peroxide has polar covalent bonds between oxygen and hydrogen atoms. The oxygen atom is more electronegative, creating a dipole moment. However, the dipole moment of H2O2 is lower than that of CH3FH2O due to the absence of hydrogen bonding.

4. BF3: Boron trifluoride is a nonpolar molecule. The fluorine atoms are more electronegative than boron, but the molecule has a trigonal planar shape, resulting in the cancellation of dipole moments. Therefore, BF3 has a dipole moment of zero.

5. NH3: Ammonia has a trigonal pyramidal shape and a polar covalent bond between nitrogen and hydrogen. The nitrogen atom is more electronegative, creating a dipole moment. However, the dipole moment of NH3 is lower than that of CH3FH2O due to the absence of hydrogen bonding.

Therefore, the correct order of dipole moment is: CH3Cl < CH3FH2O > H2O2 > BF3 > NH3.