Number of compounds/species from the following with non-zero dipole moment is_____ BeCl₂, BCl₃, NF₃, XeF₄, CCl₄, H₂O H₂S, HBr, CO₂, H₂, HCl

The correct answer is 5.

To determine the number of compounds/species with a non-zero dipole moment, we analyze the molecular geometry and symmetry of each species:
1. BeCl₂: Beryllium atom undergoes sp hybridization, resulting in a linear geometry. The two polar Be-Cl bonds are equal and opposite, canceling each other out. Thus, the dipole moment is zero ($\mu =0$).
2. BCl₃: Boron atom undergoes sp² hybridization, resulting in a symmetrical trigonal planar geometry. The individual B-Cl bond dipoles cancel each other out, so the dipole moment is zero ($\mu =0$).
3. NF₃: Nitrogen has one lone pair and three bond pairs (sp³ hybridized), resulting in an asymmetrical trigonal pyramidal geometry. The dipoles do not cancel, so the dipole moment is non-zero ($\mu \ne 0$).
4. XeF₄: Xenon has four bond pairs and two lone pairs (sp³d² hybridized), resulting in a square planar geometry. The lone pairs are positioned trans to each other and their dipoles cancel, while the four Xe-F polar bonds also cancel. Thus, the dipole moment is zero ($\mu =0$).
5. CCl₄: Carbon undergoes sp³ hybridization, resulting in a symmetrical tetrahedral geometry. The four polar C-Cl bonds cancel each other out, so the dipole moment is zero ($\mu =0$).
6. H₂O: Oxygen has two bond pairs and two lone pairs, giving it a bent (V-shaped) geometry. The bond dipoles and lone pair dipoles reinforce each other, resulting in a non-zero dipole moment ($\mu \ne 0$).
7. H₂S: Like water, sulfur has two bond pairs and two lone pairs, resulting in a bent (V-shaped) geometry. It is asymmetrical and has a non-zero dipole moment ($\mu \ne 0$).
8. HBr: This is a heteronuclear diatomic molecule with a difference in electronegativity between hydrogen and bromine, making it polar with a non-zero dipole moment ($\mu \ne 0$).
9. CO₂: Carbon is sp hybridized, resulting in a linear geometry. The two polar C=O double bonds point in opposite directions and cancel each other out. Thus, the dipole moment is zero ($\mu =0$).
10. H₂: This is a homonuclear diatomic molecule with no electronegativity difference between the atoms, so the dipole moment is zero ($\mu =0$).
11. HCl: This is a heteronuclear diatomic molecule with a difference in electronegativity between hydrogen and chlorine, giving it a polar nature and a non-zero dipole moment ($\mu \ne 0$).

The compounds/species with a non-zero dipole moment ($\mu \ne 0$) are:
NF₃, H₂O, H₂S, HBr, and HCl.

Therefore, there are 5 such compounds.