Solve this:
Q.5. In the metal carbonyls of general formula $M{\left(CO\right)}_x$ (Which follows EAN rule) if M is Ni, Fe and Cr the value of x will be respectively:-
(1) 6, 5, 6
(2) 4, 5, 6
(3) 4, 4, 5
(4) 4, 6, 6

Dear student,
EAN = Z - (oxidation state) + 2 x coordination number

For Fe;
36 = 26 - 0 + 2x; x=5; complex is Fe(CO)₅.

For Ni,
36 = 28 - 0 + 2x; x=4; complex is Ni(CO)₄.

For Cr,
36 = 24 - 0 + 2x; x=6; complex is Cr(CO)_6.
Hence,
(2) is correct option.

hope it helps
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