Find the value of x in ${\mathrm{H}}_{\mathrm{x}}\left[\mathrm{Mn}(\mathrm{CO}{)}_5\right]$: 

The value of x is 1. The compound is ${\mathrm{H}}_{\mathrm{x}}\left[\mathrm{Mn}(\mathrm{CO}{)}_5\right]$

If EAN of a central metal atom of $\mathrm{\alpha }$ complex compound no. of a noble gas.

If n, Z, an x  are the numbers of ligands, atomic Number and oxidation state of metal ion

EAN is found as,

$\begin{array}{l}\Rightarrow 36=25+x+10\\ \Rightarrow 36-35=x\\ \Rightarrow x=+1\\ 25+x+10=36\\ x=+1\end{array}$

Hence, the correct option is C