What is chemical bonding? How is it formed,and what are its types?

The numbers of lone pairs and bond pairs in hydrazine are,respectively

In which of the following are ionic,covalent,and coordinate bonds present?

What is the formal charge of oxygen atoms in carbon monoxide?

$A$ tin chloride $Q$ undergoes the following reactions (not balanced):
$Q + Cl^{-} \rightarrow X$
$Q + Me_3N \rightarrow Y$
$Q + CuCl_2 \rightarrow Z + CuCl$
$X$ is a monoanion having pyramidal geometry. Both $Y$ and $Z$ are neutral compounds. Choose the correct option$(s)$.
$(1)$ The central atom in $X$ is $sp^3$ hybridized
$(2)$ The oxidation state of the central atom in $Z$ is $+4$
$(3)$ The central atom in $Z$ has no lone pair of electrons
$(4)$ There is a coordinate bond in $Y$

Assertion : Bond angle of $H_2S$ is smaller than $H_2O$.
Reason : Electronegativity of the central atom increases,bond angle decreases.