The addition of 120mL 4mol / L of dilute nitric acid to a mixture of Fe, FeO and Fe2O3 is suitable for mixing... The addition of 120mL 4mol / L of dilute nitric acid to a mixture of Fe, FeO and Fe2O3 results in complete dissolution of the mixture and the production of 1.344 L of NO under standard conditions. The addition of KSCN solution to the resulting solution results in no blood red. If the mixture of the same mass is reduced with sufficient H2 under heating conditions, the production of iron is A,0.24mol B0.21mol C0.16mol D0.14mol The amount of iron

The addition of 120mL 4mol / L of dilute nitric acid to a mixture of Fe, FeO and Fe2O3 is suitable for mixing... The addition of 120mL 4mol / L of dilute nitric acid to a mixture of Fe, FeO and Fe2O3 results in complete dissolution of the mixture and the production of 1.344 L of NO under standard conditions. The addition of KSCN solution to the resulting solution results in no blood red. If the mixture of the same mass is reduced with sufficient H2 under heating conditions, the production of iron is A,0.24mol B0.21mol C0.16mol D0.14mol The amount of iron

Look at the answer to the unit, should be asked is the amount of material to get iron?
Should choose B.
Analyze as follows:
The presence of blood-free red by addition of KSCN indicates that only
Fe (NO3)2,
N (NO3-)=0.12 x 4-1.344/22.4=0.42(mol)
Therefore, n (Fe)= n (Fe2+)=0.42/2=0.21(mol)

To a certain amount of mixture of Fe, FeO and Fe2O3, add 120mL 4mol L of dilute nitric acid to completely dissolve the mixture, release 1.344L NO (standard condition), add KSCN solution to the resulting solution, and no red color appears. If the mixture of the same mass is reduced by heating with sufficient hydrogen, the amount of iron can be () A. 0.24 mol B. 0.21 mol C. 0.16 mol D. 0.14 mol

As a certain amount of Fe, FeO and Fe2O3 mixture is added with 120mL 4mol%/L dilute nitric acid to completely dissolve the mixture, KSCN solution is added to the resulting solution without blood red, and the amount of solute in the solution is Fe (NO3)2,1.344L NO (standard condition) is 1.344L
22.4 L/mol=0.06 mol, according to the conservation of nitrogen element, the amount of substance of nitrate ion in ferrous nitrate is 0.12 L×4 mol/L-0.06 mol=0.42 mol, so the amount of substance of ferrous nitrate is 0.42 mol
2=0.21 Mol. From the conservation of iron element, the amount of iron obtained is n (Fe)=0.21 mol.
Therefore: B.