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In the structure of the dichromate ion, there is a:

The incorrect statement among the following is:

In the given chemical reaction, colors of the \( \mathrm{Fe^{2+}} \) and \( \mathrm{Fe^{3+}} \) ions, are respectively:
\( 5\mathrm{Fe^{2+}} + \mathrm{MnO_4^-} + 8\mathrm{H^+} \rightarrow \mathrm{Mn^{2+}} + 4\mathrm{H_2O} + 5\mathrm{Fe^{3+}} \)

The number of \( f \) electrons in the ground state electronic configuration of \( \mathrm{Np} \) (\( Z = 93 \)) is __________. (Integer answer)

On complete reaction of \( \mathrm{FeCl_3} \) with oxalic acid in aqueous solution containing \( \mathrm{KOH} \), resulted in the formation of product A. The secondary valency of \( \mathrm{Fe} \) in the product A is _______. (Round off to the Nearest Integer)

The number of \( 4f \) electrons in the ground state electronic configuration of \( \mathrm{Gd^{2+}} \) is ______.
[Atomic nuclear of Gd \( = 64 \)]

The set having ion which are coloured and paramagnetic both is:

Sulphide ion is soft base and its ores are common for metals.
\( (a) \) Pb \( \quad (b) \) Al \( \quad (c) \) Ag \( \quad (d) \) Mg
Choose the correct answer from the options given below:

Given below are two statements:
Statement I : Potassium permanganate on heating at \( 573 \, \mathrm{K} \) forms potassium manganate.
Statement II : Both potassium permanganate and potassium manganate are tetrahedral and paramagnetic in nature.
In the light of the above statements, choose the most appropriate answer from the options given below:

Identify the element for which electronic configuration in \( +3 \) oxidation state is \( [\text{Ar}]3d^5 \):

Which one of the following when dissolved in water gives coloured solution in nitrogen atmosphere?

The common positive oxidation states for an element with atomic number \( 24 \), are :

The nature of oxides \( \mathrm{V_2O_3} \) and \( \mathrm{CrO} \) is indexed as 'X' and 'Y' type respectively. The correct set of X and Y is:

The number of hydrogen bonded water molecule(s) associated with stoichiometry \( \mathrm{CuSO_4\cdot 5H_2O} \) is ____________ .

\( \text{FeX}_2 \) and \( \text{FeY}_3 \) are known when x and y are:

Which one of the following lanthanides exhibits \( +2 \) oxidation state with diamagnetic nature? (Given \( Z \) for Nd \( = 60 \), Yb \( = 70 \), La \( = 57 \), Ce \( = 58 \))

What is the correct order of the following elements with respect to their density?

The correct order of following \( 3d \) metal oxides, according to their oxidation numbers is:
(a) \( \mathrm{CrO_3} \) (b) \( \mathrm{Fe_2O_3} \) (c) \( \mathrm{MnO_2} \) (d) \( \mathrm{V_2O_5} \) (e) \( \mathrm{Cu_2O} \)

An inorganic Compound ‘X’ on treatment with concentrated \( \text{H}_2\text{SO}_4 \) produces brown fumes and gives dark brown ring with \( \text{FeSO}_4 \) in presence of concentrated \( \text{H}_2\text{SO}_4 \). Also Compound ‘X’ gives precipitate ‘Y’, when its solution in dilute \( \text{HCl} \) is treated with \( \text{H}_2\text{S} \) gas. The precipitate ‘Y’ on treatment with concentrated \( \text{HNO}_3 \) followed by excess of \( \text{NH}_4\text{OH} \) further gives deep blue coloured solution, Compound ‘X’ is:

Number of electrons present in \( 4f \) orbital of \( \mathrm{Ho^{3+}} \) ion is _______. (Given Atomic No. of \( \mathrm{Ho} = 67 \))

Potassium permanganate on heating at \( 513 \, \mathrm{K} \) gives a product which is:

The spin only magnetic moments (in BM) for free \( \mathrm{Ti}^{3+} \), \( \mathrm{V}^{2+} \) and \( \mathrm{Sc}^{3+} \) ions respectively are: (Atomic No. \( \mathrm{Sc} = 21 \), \( \mathrm{Ti} = 22 \), \( \mathrm{V} = 23 \))

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JEE Main 2021 26th August Morning Shift

The number of \( 4f \) electrons in the ground state electronic configuration of \( \mathrm{Gd^{2+}} \) is ______.
[Atomic nuclear of Gd \( = 64 \)]