MCQ
The oxidation number of cobalt in $\mathrm{K}\left[\mathrm{Co}(\mathrm{CO})_4\right]$ is:
- A$+1$
- B$+3$
- ✓$–1$
- D$–3$
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${\left[ {Fe{{\left( {CN} \right)}_6}} \right]^{ - 4}}\,\xrightarrow{{MnO_4^ - /{H^ + }}}F{e^{ + 3}} + C{O_2} + NO_3^ - $
$B$ is green colored compound then it would be