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प्रश्न
In the form of dichromate, \[\ce{Cr (VI)}\] is a strong oxidising agent in acidic medium but \[\ce{Mo (VI)}\] in \[\ce{MoO3}\] \[\ce{and W (VI)}\] in \[\ce{WO3}\] are not because:
(i) \[\ce{Cr(VI)}\] is more stable than \[\ce{Mo(VI)}\] and \[\ce{and W(VI)}\].
(ii) \[\ce{Mo(VI)}\] and \[\ce{and W(VI)}\] are more stable than \[\ce{Cr(VI)}\].
(iii) Higher oxidation states of heavier members of group-6 of transition series are more stable.
(iv) Lower oxidation states of heavier members of group-6 of transition series are more stable.
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उत्तर
(ii) \[\ce{Mo(VI)}\] and \[\ce{and W(VI)}\] are more stable than \[\ce{Cr(VI)}\].
(iii) Higher oxidation states of heavier members of group-6 of transition series are more stable.
Explanation:
In d-block elements, for heavier elements, the higher oxidation states are more stable. Hence, \[\ce{Mo(VI)}\] and \[\ce{W(VI)}\] are more stable than \[\ce{Cr(VI)}\]. That’s why, \[\ce{Cr(VI)}\] in the form of dichromate is a stronger oxidizing agent in acidic medium whereas \[\ce{MoO3}\] and \[\ce{WO3}\] are not.
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संबंधित प्रश्न
Complete the following chemical equation
8MnO4- + 3S2O32- + H2O →
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Give an example and suggest a reason for the following feature of the transition metal chemistry:
The highest oxidation state is exhibited in oxoanions of a metal.
Write the formula of an oxo-anion of Manganese (Mn) in which it shows the oxidation state equal to its group number.
E0 value for Mn3+ Mn2+ couple is much more positive than that for Cr3-/ Cr2-.
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On addition of small amount of \[\ce{KMnO4}\] to concentrated \[\ce{H2SO4}\], a green oily compound is obtained which is highly explosive in nature. Identify the compound from the following.
Which of the following is amphoteric oxide?
\[\ce{Mn2O7, CrO3, Cr2O3, CrO, V2O5, V2O4}\]
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Generally transition elements and their salts are coloured due to the presence of unpaired electrons in metal ions. Which of the following compounds are coloured?
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(ii) \[\ce{Ce(SO4)2}\]
(iii) \[\ce{TiCl}\]
(iv) \[\ce{Cu2 Cl2}\]
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Why \[\ce{HCl}\] should not be used for potassium permanganate titrations?
Indicate the steps in the preparation of \[\ce{K2Cr2O2}\] from chromite ore.
Indicate the steps in the preparation of \[\ce{K2Cr2O7}\] from chomite ore.
Indicate the steps in the preparation of \[\ce{K2Cr2O7}\] from chromite ore.
Indicate the steps in the preparation of \[\ce{K2Cr2O7}\] from chromite ore.
Describe the preparation of potassium permanganate. How does the acidified permanganate solution react with SO2? Write the ionic equation for the reaction.
Describe the preparation of potassium permanganate. How does the acidified permanganate solution react with oxalic acid? Write the ionic equation for the reaction.
