d - block and f - block Elements
Which of the following is an amphoteric oxide?
Name the oxometal anions of the first series of the transition metals in which the metal exhibits the oxidation state equal to its group number.
$$\displaystyle MnO_4^- :$$ Mn has +7 oxidation number and group number is 7.
$$\displaystyle CrO_4^{2-} : $$ Cr has +6 oxidation state and group number is 6.
$${VO}_{3}^{-}:$$ V has +5 oxidation state and the group number is 5.
Which of the following is an amphoteric oxide?
Which of the following compound is blue?
Which of the following oxides are basic in nature ?
Zinc oxide is normally white but turns yellow on heating and becomes white again on cooling because of:
The Oxidation states of $$Cr$$ in $$[Cr(H_2O)_6]Cl_3, [Cr(C_6H_6)_2]$$, and $$K_2[Cr(CN)_2(O)_2(O_2)(NH_3]$$ respectively are:
Which of the following compounds is metallic and ferromagnetic?
In acidic medium, $$H_2O_2$$ changes $$Cr_2O_7^{- 2}$$ to $$CrO_5$$ which has two ($$-O- O-$$) bonds oxidation state of $$Cr$$ in $$CrO_5$$ is:
$$Cr - C$$ bond in the compound $$[Cr(CO)_6]$$ shows $$\pi$$ - character due to :
Passivity of iron is due to formation of:
Fe is made passive by: