Find the coordination number and oxidation number of X in the given compound.

[X(NH${}_3$)${}_5$(SO${}_4$)]CI.

The coordination number and oxidation number of X in the given compound [X(NH${}_3$)${}_5$(SO${}_4$)]CI are 6 and 3 respectively. Five ammonia and one sulphate ligands are present. Hence, the coordination number is 6.Let the oxidation number of X be Y.
$Y+5\left(0\right)+(2-)-1=0$
$Y=3$.