Sir i am not able to understand coordinate bond clearly . As i am late comer so can you grant me short formulas like formal charge,bond pair etc. I can understand hindi so you can grant me video in hindi. Thank you

Dear student,
A coordinate bond is a type of covalent bond formed between two species in which shared pair of electrons is denoted by one species only but shared by both species. It is also known as dative bond. 

For example:

NH₃ shares the pair of electrons present on Nitrogen with BF₃, which is electron deficient.

Hence when in a bond between two species both the electrons are donated by one atom (unlike covalent bond in which both the atoms donate one electron each), the bond will be coordinate bond. The coordinate bond is denoted by an arrow from the donor atom of the electron donating species to the acceptor atom of the electron deficient species.

The formal charge is the difference in the number of valence electrons in the atom and the number of valence electrons in the Lewis structure.
The formal charge of any atom in a molecule can be calculated by the following equation:
FC = V– N–B/2
Where V is the number of valence elctrons of the atom in the free atom; N is the number of non-bonding electrons on this atom in the molecule; and B is the total number of electrons shared in covalent bonds with other atoms in the molecule. For example: In O₃ molecule 


Regards