Among the following oxides of 3d elements, the number of mixed oxides are . Ti2O3, V2O4, Cr2O3, Mn3O4, Fe3O4, Fe2O3, Co3O4
3
A mixed oxide contains the metal in two oxidation states (MO·M₂O₃ type).
Mn3O4 = MnO Mn2O3 (Mn +2, +3) ⇒ mixed
Fe3O4 = FeO Fe2O3 (Fe +2, +3) ⇒ mixed
Co3O4 = CoO Co2O3 (Co +2, +3) ⇒ mixed
Ti2O3 (+3), V2O4 (+4), Cr2O3 (+3), Fe2O3 (+3) ⇒ single oxidation state
Number of mixed oxides = 3
Answer: 3
MnO42-, in acidic medium, disproportionates to :
Consider the following reactions : NaCl + K2Cr2O7 + H2SO4 A + KHSO4 + NaHSO4 + H2O A + NaOH B + NaCl + H2O B + H2SO4 + H2O2 C + Na2SO4 + H2O In the product 'C', 'X' is the number of O22- units, 'Y' is the total number of oxygen atoms present and 'Z' is the oxidation state of Cr. The value of X + Y + Z is .
Given below are some of the statements about Mn and Mn2O7. Identify the correct statements. Choose the correct answer from the options given below :
The correct decreasing order of spin only magnetic moment values (BM) of Cu+, Cu2+, Cr2+ and Cr3+ ions is :
The first transition series metal 'M' has the highest enthalpy of atomisation in its series. One of its aquated ions ( Mn+) exists in green colour. The nature of the oxide formed by the above Mn+ ion is:
The number of valence electrons present in the metal among Cr, Co, Fe and Ni which has the lowest enthalpy of atomisation is :
'X' is the number of acidic oxides among VO2, V2O3, CrO3, V2O5 and Mn2O7. The primary valency of cobalt in [Co(H2NCH2CH2NH2)3]2(SO4)3 is Y. The value of X + Y is .
Pair of transition metal ions having the same number of unpaired electrons is
KMnO4 acts as an oxidising agent in acidic medium. 'X' is the difference between the oxidation states of Mn in reactant and product. 'Y' is the number of 'd' electrons present in the brown red precipitate formed at the end of the acetate ion test with neutral ferric chloride. The value of X + Y is .
The incorrect relationship in the following pairs in relation to ionisation enthalpies is :