The central atom of ammonia is nitrogen and it has 3 bonding pairs and a lone pair around, hence it undergoes sp3 hybridization. The central atom of boron trifluoride is the boron atom, and around it has only three bonding pairs. So it hybridizes as sp2.
sp2
The central atom in sulfur trioxide (SO3) is sulfur. Sulfur has 3 oxygen atoms bonded to it, forming a trigonal planar molecular geometry. Each oxygen atom is also attached to the sulfur atom through a double bond. Therefore, the hybridization of the sulfur atom in sulfur trioxide is sp2.
In aspartic acid, the carbon atoms in the carboxylic acid group and amino group are sp2 hybridized, while the central carbon is sp3 hybridized. The oxygen atom in the carboxylic acid group is also sp2 hybridized.
Carbon rehybridizes from sp3 to sp2 in tin chemistry due to the formation of a coordinate covalent bond between carbon and tin. This leads to the promotion of one electron from a lone pair orbital on carbon to form a π bond with tin, requiring the carbon to undergo sp3 to sp2 hybridization to accommodate the new bonding situation.
sp2
The central atom in SO2 is sulfur. The sulfur atom in SO2 undergoes sp2 hybridization, forming three sp2 hybrid orbitals and one unhybridized p orbital.
The central atom in BCl3 is boron, which has only three valence electrons. Since it forms three bonds with the chlorine atoms, the hybridization of the central boron atom is sp2.
The central carbon atom in CO2 has a hybridization of sp2. This means that the carbon atom uses one s orbital and two p orbitals to form three sp2 hybrid orbitals for bonding.
The central atom of ammonia is nitrogen and it has 3 bonding pairs and a lone pair around, hence it undergoes sp3 hybridization. The central atom of boron trifluoride is the boron atom, and around it has only three bonding pairs. So it hybridizes as sp2.
sp2 since the (graphical, with respect to resonance) Lewis structure for NO3- is: one oxygen double bond, the other two is single bond. an electron of N (which have 5 valence e-) is "donated" to O. And an electron gained by the anion is placed on the other O.
The central atom in ClO3 is Cl (chlorine). It forms three sigma bonds with the oxygen atoms, leading to a trigonal planar molecular geometry. The hybridization of the central Cl atom is sp2.
The central atom in BF3, boron, undergoes sp2 hybridization. This means that the 2s and two of the 2p orbitals of boron hybridize to form three sp2 hybrid orbitals, which are then used for bonding with the three fluorine atoms.
The central atom in COCl2 is carbon. The carbon atom is sp2 hybridized in COCl2, meaning it has three electron pairs in sp2 hybrid orbitals and forms sigma bonds with three surrounding atoms in a trigonal planar geometry.
Prsumably you mean AlH4- the tetrahydroaluminate anion. The hybridization of the central atom of AlH4 is sp3.
sp2
The nitrogen atom of pyridine is sp2 hybridized. It participates in the aromatic ring system of pyridine and forms three sigma bonds with neighboring carbon atoms, resulting in the sp2 hybridization.