How many different types of $O-B-O$ angles are there in sodium peroxoborate?

The $[Co(H_2O)_6]^{2+}$ ion has three unpaired electrons. The hybridization of $Co$ in $[Co(H_2O)_6]^{2+}$ is

Identify,from the following,the diamagnetic,tetrahedral complex.

Nickel $(Z = 28)$ forms a paramagnetic complex $[NiX_4]^{2-}$ with a uninegative monodentate ligand $X^-$. The number of unpaired electrons in nickel and the geometry of this complex ion are,respectively:

Consider the reaction $CuSO_4 + KCN \to CuCN + Y \xrightarrow{\text{excess } K^{+}CN^{-}} Z$. Identify the correct statement regarding the products $Y$ and $Z$.

Using valence bond theory,explain the following in relation to the complexes given below: $[Mn(CN)_{6}]^{3-}, [Co(NH_{3})_{6}]^{3+}, [Cr(H_{2}O)_{6}]^{3+}, [FeCl_{6}]^{4-}$
$(i)$ Type of hybridisation.
$(ii)$ Inner or outer orbital complex.
$(iii)$ Magnetic behaviour.
$(iv)$ Spin only magnetic moment value.