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The oxidation state of chromium in the final product formed in the reaction between KI and acidified K2Cr2O7 solution is :
(2) +3
Acidified dichromate oxidises iodide to iodine and is itself reduced to Cr3+:
Cr2O72- + 14H+ + 6I- 2Cr3+ + 3I2 + 7H2O
Oxidation state of Cr changes from +6 (in Cr2O72-) to +3 (in Cr3+).
Answer: (2)
Given below are two statements : In the light of the above statements, choose the correct answer from the options given below :
Among the following oxides of 3d elements, the number of mixed oxides are . Ti2O3, V2O4, Cr2O3, Mn3O4, Fe3O4, Fe2O3, Co3O4
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