To determine the oxidation state of the central atom Fe in the compound [Fe CN 6]4-, we first need to know the oxidation state of the other atoms in the compound.The cyanide ion CN- has an overall charge of -1. Since there are six cyanide ions in the compound, the total charge contributed by the cyanide ions is -6.The overall charge of the compound is -4, as given in the problem. To balance the charges, the oxidation state of the central atom Fe must be:Fe + -6 = -4Fe = -4 + 6Fe = +2So, the oxidation state of the central atom Fe in the compound [Fe CN 6]4- is +2.