Discussion Forum



1)

To an evacuated vessel with movable piston under the external pressure of 1 atm, 0.1 mole of He and 1.0 mole of an unknown compound (vapour pressure 0.68 atm at 0 °C) are introduced. Considering the ideal gas behaviour, the total volume (in litre) of the gases at 0°C is close to


A) 4

B) 6

C) 5

D) 7

Answer:

Option D

Explanation:

Haematite is Fe2O3, in which the oxidation number of iron is III. Magnetite is Fe3O4 which is in fact a mixed oxide (FeO.Fe2O3 ) . Hence,iron is present in both ll and lll oxidation state.