Bonds present in $CuSO_4 \cdot 5H_2O$ are

How many $S-S$ bonds are present in the cyclic trimer of sulfur trioxide,$(SO_3)_3$?

Which of the following species contains an equal number of $\sigma -$ and $\pi -$ bonds?

Amongst the following,the total number of species $NOT$ having $8$ electrons around the central atom in its outermost shell is $NH_3$,$AlCl_3$,$BeCl_2$,$CCl_4$,$PCl_5$:

The formal charges of $N_{(1)}$,$N_{(2)}$ and $O$ atoms in the structure shown below are respectively:
$:N_{(1)}=N_{(2)}=\ddot{O}:$

Identify the thermal decomposition reactions that evolve a gas containing an equal number of $\sigma$ and $\pi$ bonds.
$(a)$ $BeCO_3 \xrightarrow{\Delta } BeO + CO_2$
$(b)$ $Fe_2(SO_4)_3 \xrightarrow{\Delta } Fe_2O_3 + 3SO_3$
$(c)$ $FeSO_4 \xrightarrow{\Delta } Fe_2O_3 + SO_2 + SO_3$
$(d)$ $(NH_4)_2Cr_2O_7 \xrightarrow{\Delta } Cr_2O_3 + N_2 + 4H_2O$
$(e)$ $ZnSO_4 \xrightarrow{\Delta } ZnO + SO_3$
$(f)$ $NH_4Cl \xrightarrow{\Delta } NH_3 + HCl$