Given below are two statements :

Statement I : The number of pairs, from the following, in which both the ions are coloured in aqueous solution is 3.

$ \left[\mathrm{Sc}^{3+}, \mathrm{Ti}^{3+}\right],\left[\mathrm{Mn}^{2+}, \mathrm{Cr}^{2+}\right],\left[\mathrm{Cu}^{2+}, \mathrm{Zn}^{2+}\right] \text { and }\left[\mathrm{Ni}^{2+}, \mathrm{Ti}^{4+}\right] $

Statement II : $\mathrm{Th}^{4+}$ is the strongest reducing agent among $\mathrm{Th}^{4+}, \mathrm{Ce}^{4+}, \mathrm{Gd}^{3+}$ and $\mathrm{Eu}^{2+}$.

In the light of the above statements, choose the correct answer from the options given below

Given below are two statements :

Statement I : The first ionization enthalpy of Cr is lower than that of Mn .

Statement II : The second and third ionization enthalpies of Cr are higher than those of Mn .

In the light of the above statements, choose the correct answer from the options given below :

On heating a mixture of common salt and $K_2Cr_2O_7$ in equal amount along with concentrated $H_2SO_4$ in a test tube, a gas is evolved. Formula of the gas evolved and oxidation state of the central metal atom in the gas respectively are:

A. Mn forms the oxide $\mathrm{Mn_2O_7}$, in which Mn is in its highest oxidation state.

B. Oxygen stabilizes the Mn in higher oxidation states by forming multiple bonds with Mn.

C. $\mathrm{Mn_2O_7}$ is an ionic oxide.

D. The structure of $\mathrm{Mn_2O_7}$ consists of one bridged oxygen.

Choose the correct answer from the options given below :

$\mathrm{MnO}_4{ }^{2-}$, in acidic medium, disproportionates to :

Given below are two statements :

Statement I : The number of pairs among $\left[\mathrm{Ti}^{4+}, \mathrm{V}^{2+}\right],\left[\mathrm{V}^{2+}, \mathrm{Mn}^{2+}\right],\left[\mathrm{Mn}^{2+}, \mathrm{Fe}^{3+}\right]$ and $\left[\mathrm{V}^{2+}, \mathrm{Cr}^{2+}\right]$ in which both ions are coloured is 3 .

Statement II : The number of pairs among $\left[\mathrm{La}^{3+}, \mathrm{Yb}^{2+}\right],\left[\mathrm{Lu}^{3+}, \mathrm{Ce}^{4+}\right]$ and $\left[\mathrm{Ac}^{3+}, \mathrm{Lr}^{3+}\right]$ ions in which both are diamagnetic is 3 .

In the light of the above statements, choose the correct from the options given below :

Given below are two statements for catalytic properties of transition metals.

Statement I : First row transition metals which act as catalyst utilise their 3d electrons only for formation of bonds between reactant molecules and atoms on the surface of catalyst.

Statement II : There is increase in the concentration of reactants on the surface of catalyst which strengthens the bonds in reacting molecules.

In the light of the above statements, choose the correct answer from the options given below :

The correct order of first $\left(\Delta_i \mathrm{H}_1\right)$ and second $\left(\Delta_i \mathrm{H}_2\right)$ ionisation enthalpy values of Cr and Mn are :

A. $\Delta_i \mathrm{H}_1: \mathrm{Cr}>\mathrm{Mn}$

B. $\Delta_i \mathrm{H}_2: \mathrm{Cr}>\mathrm{Mn}$

C. $\Delta_i \mathrm{H}_1: \mathrm{Mn}>\mathrm{Cr}$

D. $\Delta_i \mathrm{H}_2: \mathrm{Mn}>\mathrm{Cr}$

Choose the correct answer from the options given below :

The correct statements among the following are :

A. Basic vanadium oxide is used in the manufacture of $\mathrm{H}_2 \mathrm{SO}_4$.

B. The spin-only magnetic moment value of the transition metal halide employed in Ziegler-Natta polymerization is 2.84 BM .

C. The p-block metal compound employed in Ziegler-Natta polymerization has the metal in +3 oxidation state.

D. The number of electrons present in the outer most ' d ' orbital of metal halide employed in Wacker process is 8.

Choose the correct answer from the options given below :

A paper dipped in a dil. $\mathrm{H}_2 \mathrm{SO}_4$ solution of ' $X$ ' upon treatment with $\mathrm{SO}_2$ gas turns into green. The compound ' $X$ ' is :

Which of the following is NOT a physical or chemical characteristics of interstitial compounds?

Pairs of elements with the same number of electrons in their respective 4f orbital are

[Atomic number. Eu-63, Gd-64, Dy-66, Ho-67, Tm-69, Yb-70, Lu-71, Hf-72]

A. (Eu and Gd)

B. (Dy and Ho)

C. ( Yb and Hf )

D. ( Lu and Tm)

Choose the correct answer from the options given below :

Consider $|x|$ is the difference in oxidation states of Mn in highest manganese fluoride and highest manganese oxide. The ions with $|x|$ number of unpaired electrons from the following are :

A. $\mathrm{Sc}^{3+}$

B. $\mathrm{Zn}^{2+}$

C. $\mathrm{V}^{2+}$

D. $\mathrm{Fe}^{2+}$

E. $\mathrm{Co}^{2+}$

Choose the correct answer from the options given below :

The correct statements among the following are,

A. $\mathrm{Mo}(\mathrm{VI})$ and $\mathrm{W}(\mathrm{VI})$ are less stable than $\mathrm{Cr}(\mathrm{VI})$.

B. $\mathrm{Ce}^{4+}$ and $\mathrm{Tb}^{4+}$ are oxidant while $\mathrm{Eu}^{2+}$ and $\mathrm{Yb}^{2+}$ are reductant.

C. Cm and Am have seven unpaired electrons.

D. Actinoid contraction is greater from element to element than lanthanoid contraction.

Choose the correct answer from the options given below :

Correct statements from the following are

A. Potassium dichromate is an oxidising agent and it oxidises $\mathrm{FeSO}_4$ to $\mathrm{Fe}_2\left(\mathrm{SO}_4\right)_3$ in acidic medium.

B. Sodium dichromate can be used as primary standard in volumetric estimation.

C. $\mathrm{CrO}_4^{2-}$ and $\mathrm{Cr}_2 \mathrm{O}_7^{2-}$ are interconvertible in aqueous solution by varying the pH of the solution.

D. $\mathrm{Cr}-\mathrm{O}-\mathrm{Cr}$ bond angle in $\mathrm{Cr}_2 \mathrm{O}_7^{2-}$ is $126^{\circ}$.

Choose the correct answer from the options given below :

Among $Fe^{2+}$, $Fe^{3+}$, $Cr^{2+}$ and $Zn^{2+}$, the ion that shows positive borax bead test and with highest ionisation enthalpy is :

Which of the following sets includes all the species that will change the orange colour of $\mathrm{K_2Cr_2O_7}$ in acidic medium?

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 ion $\left(\mathrm{M}^{\mathrm{n}+}\right)$ exists in green colour. The nature of the oxide formed by the above $\mathrm{M}^{\mathrm{n}+}$ ion is:

Pair of transition metal ions having the same number of unpaired electrons is

Given below are two statements:

Statement I : $\mathrm{CrO}_3$ is a stronger oxidizing agent than $\mathrm{MoO}_3$

Statement II : $\mathrm{Cr}(\mathrm{VI})$ is more stable than $\mathrm{Mo}(\mathrm{VI})$

In the light of the above statements, choose the correct answer from the options given below

The metal ions that have the calculated spin-only magnetic moment value of 4.9 B.M. are :

A. $\mathrm{Cr}^{2+}$

B. $\mathrm{Fe}^{2+}$

C. $\mathrm{Fe}^{3+}$

D. $\mathrm{Co}^{2+}$

E. $\mathrm{Mn}^{3+}$

Choose the correct answer from the options given below:

The correct option with order of melting points of the pairs (Mn, Fe), (Tc, Ru) and (Re, Os) is :

The metal ion whose electronic configuration is not affected by the nature of the ligand and which gives a violet colour in non-luminous flame under hot condition in borax bead test is

Match List - I with List - II.

Choose the correct answer from the options given below :

Preparation of potassium permanganate from $\mathrm{MnO}_2$ involves two step process in which the 1st step is a reaction with KOH and $\mathrm{KNO}_3$ to produce

Which of the following ions is the strongest oxidizing agent? (Atomic Number of $\mathrm{Ce}=58, \mathrm{Eu}=63, \mathrm{~Tb}=65, \mathrm{Lu}=71$)

Match List - I with List - II

Choose the correct answer from the options given below :

Consider the following reactions

$\mathrm{K}_2 \mathrm{Cr}_2 \mathrm{O}_7 \xrightarrow[-\mathrm{H}_2 \mathrm{O}]{\mathrm{KOH}}[\mathrm{~A}] \xrightarrow[-\mathrm{H}_2 \mathrm{O}]{\mathrm{H}_2 \mathrm{SO}_4}[\mathrm{~B}]+\mathrm{K}_2 \mathrm{SO}_4$

The products $[A]$ and $[B]$, respectively are :

The correct set of ions (aqueous solution) with same colour from the following is:

Lanthanoid ions with $4 \mathrm{f}^7$ configuration are :

(A) $\mathrm{Eu}^{2+}$

(B) $\mathrm{Gd}^{3+}$

(C) $\mathrm{Eu}^{3+}$

(D) $\mathrm{Tb}^{3+}$

(E) $ \mathrm{Sm}^{2+}$

Choose the correct answer from the options given below :

The electronic configuration of Einsteinium is :

(Given atomic number of Einsteinium $=99$)

Give below are two statements :

Statement I : The higher oxidation states are more stable down the group among transition elements unlike p-block elements.

Statement II : Copper can not liberate hydrogen from weak acids.

In the light of the above statements, choose the correct answer from the options given below :

The electronic configuration of $\mathrm{Cu}(\mathrm{II})$ is $3 \mathrm{~d}^9$ whereas that of $\mathrm{Cu}(\mathrm{I})$ is $3 \mathrm{~d}^{10}$. Which of the following is correct?

Iron (III) catalyses the reaction between iodide and persulphate ions, in which

A. $\mathrm{Fe}^{3+}$ oxidises the iodide ion

B. $\mathrm{Fe}^{3+}$ oxidises the persulphate ion

C. $\mathrm{Fe}^{2+}$ reduces the iodide ion

D. $\mathrm{Fe}^{2+}$ reduces the persulphate ion

Choose the most appropriate answer from the options given below:

Arrange the following elements in the increasing order of number of unpaired electrons in it.

(A) $\mathrm{Sc}$

(B) $\mathrm{Cr}$

(C) $\mathrm{V}$

(D) $\mathrm{Ti}$

(E) $\mathrm{Mn}$

Choose the correct answer from the options given below :

The number of element from the following that do not belong to lanthanoids is $\mathrm{Eu}, \mathrm{Cm}, \mathrm{Er}, \mathrm{Tb}, \mathrm{Yb}$ and $\mathrm{Lu}$

While preparing crystals of Mohr's salt, dil $\mathrm{H}_2 \mathrm{SO}_4$ is added to a mixture of ferrous sulphate and ammonium sulphate, before dissolving this mixture in water, dil $\mathrm{H_2SO_4}$ is added here to :

The number of ions from the following that have the ability to liberate hydrogen from a dilute acid is _________.

$\mathrm{Ti}^{2+}, \mathrm{Cr}^{2+} \text { and } \mathrm{V}^{2+}$

The metal that shows highest and maximum number of oxidation state is :

The element which shows only one oxidation state other than its elemental form is :

Choose the correct statements from the following

A. $\mathrm{Mn}_2 \mathrm{O}_7$ is an oil at room temperature

B. $\mathrm{V}_2 \mathrm{O}_4$ reacts with acid to give $\mathrm{VO}_2{ }^{2+}$

C. $\mathrm{CrO}$ is a basic oxide

D. $\mathrm{V}_2 \mathrm{O}_5$ does not react with acid

Choose the correct answer from the options given below :

Identify correct statements from below:

A. The chromate ion is square planar.

B. Dichromates are generally prepared from chromates.

C. The green manganate ion is diamagnetic.

D. Dark green coloured $\mathrm{K}_2 \mathrm{MnO}_4$ disproportionates in a neutral or acidic medium to give permanganate.

E. With increasing oxidation number of transition metal, ionic character of the oxides decreases.

Choose the correct answer from the options given below:

The metals that are employed in the battery industries are

A. $\mathrm{Fe}$

B. $\mathrm{Mn}$

C. $\mathrm{Ni}$

D. $\mathrm{Cr}$

E. $\mathrm{Cd}$

Choose the correct answer from the options given below:

The orange colour of $\mathrm{K}_2 \mathrm{Cr}_2 \mathrm{O}_7$ and purple colour of $\mathrm{KMnO}_4$ is due to

Diamagnetic Lanthanoid ions are :

Which of the following acts as a strong reducing agent? (Atomic number: $\mathrm{Ce}=58, \mathrm{Eu}=63, \mathrm{Gd}=64, \mathrm{Lu}=71$)

Which of the following statements are correct about $\mathrm{Zn}, \mathrm{Cd}$ and $\mathrm{Hg}$ ?

A. They exhibit high enthalpy of atomization as the d-subshell is full.

B. $\mathrm{Zn}$ and $\mathrm{Cd}$ do not show variable oxidation state while $\mathrm{Hg}$ shows $+\mathrm{I}$ and $+\mathrm{II}$.

C. Compounds of $\mathrm{Zn}, \mathrm{Cd}$ and $\mathrm{Hg}$ are paramagnetic in nature.

D. $\mathrm{Zn}, \mathrm{Cd}$ and $\mathrm{Hg}$ are called soft metals.

Choose the most appropriate from the options given below:

The correct IUPAC name of $\mathrm{K}_2 \mathrm{MnO}_4$ is

$\mathrm{KMnO}_4$ decomposes on heating at $513 \mathrm{~K}$ to form $\mathrm{O}_2$ along with

Given below are two statements :

Statement (I) : In the Lanthanoids, the formation $\mathrm{Ce}^{+4}$ is favoured by its noble gas configuration.

Statement (II) : $\mathrm{Ce}^{+4}$ is a strong oxidant reverting to the common +3 state.

In the light of the above statements, choose the most appropriate answer from the options given below :

Choose the correct option having all the elements with $\mathrm{d}^{10}$ electronic configuration from the following :

Which of the following electronic configuration would be associated with the highest magnetic moment?

$\mathrm{NaCl}$ reacts with conc. $\mathrm{H}_2 \mathrm{SO}_4$ and $\mathrm{K}_2 \mathrm{Cr}_2 \mathrm{O}_7$ to give reddish fumes (B), which react with $\mathrm{NaOH}$ to give yellow solution (C). (B) and (C) respectively are ;

The electronic configuration for Neodymium is:

[Atomic Number for Neodymium 60]

The pair of lanthanides in which both elements have high third - ionization energy is :

Given below are two statement: one is labelled as Assertion $\mathbf{A}$ and the other is labelled as Reason $\mathbf{R}$

Assertion A: $5 \mathrm{f}$ electrons can participate in bonding to a far greater extent than $4 \mathrm{f}$ electrons

Reason R: $5 \mathrm{f}$ orbitals are not as buried as $4 \mathrm{f}$ orbitals

In the light of the above statements, choose the correct answer from the options given below

Prolonged heating is avoided during the preparation of ferrous ammonium sulphate to :

Which of the following statements are correct?

(A) The M$^{3+}$/M$^{2+}$ reduction potential for iron is greater than manganese.

(B) The higher oxidation states of first row d-block elements get stabilized by oxide ion.

(C) Aqueous solution of Cr$^{2+}$ can liberate hydrogen from dilute acid.

(D) Magnetic moment of V$^{2+}$ is observed between 4.4 - 5.2 BM.

Choose the correct answer from the options given below :

Which halogen is known to cause the reaction given below :

$2 \mathrm{Cu}^{2+}+4 \mathrm{X}^{-} \rightarrow \mathrm{Cu}_{2} \mathrm{X}_{2}(\mathrm{s})+\mathrm{X}_{2}$

In chromyl chloride, the number of d-electrons present on chromium is same as in

(Given at no. of $\mathrm{Ti}: 22, \mathrm{~V}: 23, \mathrm{Cr}: 24, \mathrm{Mn}: 25, \mathrm{Fe}: 26$ )

Element not present in Nessler's reagent is :

Given below are two statements: one is labelled as "Assertion A" and the other is labelled as "Reason R"

Assertion A : In the complex $\mathrm{Ni}(\mathrm{CO})_{4}$ and $\mathrm{Fe}(\mathrm{CO})_{5}$, the metals have zero oxidation state.

Reason R : Low oxidation states are found when a complex has ligands capable of $\pi$-donor character in addition to the $\sigma$-bonding.

In the light of the above statements, choose the most appropriate answer from the options given below

During the reaction of permanganate with thiosulphate, the change in oxidation of manganese occurs by value of 3. Identify which of the below medium will favour the reaction.

Strong reducing and oxidizing agents among the following, respectively, are :

Which element is not present in Nessler's reagent?

Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).

Assertion (A) : $\mathrm{Cu^{2+}}$ in water is more stable than $\mathrm{Cu^{+}}$.

Reason (R) : Enthalpy of hydration for $\mathrm{Cu^{2+}}$ is much less than that of $\mathrm{Cu^{+}}$.

In the light of the above statements, choose the correct answer from the options given below :

Highest oxidation state of Mn is exhibited in $\mathrm{Mn_2O_7}$. The correct statements about $\mathrm{Mn_2O_7}$ are

(A) Mn is tetrahedrally surrounded by oxygen atoms.

(B) Mn is octahedrally surrounded by oxygen atoms.

(C) Contains Mn-O-Mn bridge.

(D) Contains Mn-Mn bond.

Choose the correct answer from the options given below :

When $\mathrm{Cu}^{2+}$ ion is treated with $\mathrm{KI}$, a white precipitate, $\mathrm{X}$ appears in solution. The solution is titrated with sodium thiosulphate, the compound $\mathrm{Y}$ is formed. $\mathrm{X}$ and $\mathrm{Y}$ respectively are :

$\mathrm{Nd^{2+}}$ = __________

The correct order of basicity of oxides of vanadium is :

During the qualitative analysis of $\mathrm{SO}_{3}^{2-}$ using dilute $\mathrm{H}_{2} \mathrm{SO}_{4}, \mathrm{SO}_{2}$ gas is evolved which turns $\mathrm{K}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}$ solution (acidified with dilute $\mathrm{H}_{2} \mathrm{SO}_{4}$) :

Given below are two statements :

Statement I : Nickel is being used as the catalyst for producing syn gas and edible fats.

Statement II : Silicon forms both electron rich and electron deficient hydrides.

In the light of the above statements, choose the most appropriate answer from the options given below :

The set of correct statements is :

(i) Manganese exhibits +7 oxidation state in its oxide.

(ii) Ruthenium and Osmium exhibit +8 oxidation in their oxides.

(iii) Sc shows +4 oxidation state which is oxidizing in nature.

(iv) Cr shows oxidising nature in +6 oxidation state.

An indicator 'X' is used for studying the effect of variation in concentration of iodide on the rate of reaction of iodide ion with $\mathrm{H_2O_2}$ at room temp. The indicator 'X' forms blue coloured complex with compound 'A' present in the solution. The indicator 'X' and compound 'A' respectively are :

A chloride salt solution acidified with dil.HNO$_3$ gives a curdy white precipitate, [A], on addition of AgNO$_3$. [A] on treatment with NH$_4$OH gives a clear solution B. A and B are respectively :

Which one amongst the following are good oxidizing agents?

A. Sm$^{2+}$

B. Ce$^{2+}$

C. Ce$^{4+}$

D. Tb$^{4+}$

Choose the most appropriate answer from the options given below :

An ammoniacal metal salt solution gives a brilliant red precipitate on addition of dimethylglyoxime. The metal ion is :

Which of the following $3\mathrm{d}$-metal ion will give the lowest enthalpy of hydration $\left(\Delta_{\text {hyd }} \mathrm{H}\right)$ when dissolved in water ?

The reaction of zinc with excess of aqueous alkali, evolves hydrogen gas and gives :

In following pairs, the one in which both transition metal ions are colourless is :

In neutral or faintly alkaline medium, $\mathrm{KMnO}_{4}$ being a powerful oxidant can oxidize, thiosulphate almost quantitatively, to sulphate. In this reaction overall change in oxidation state of manganese will be :

Match List - I with List - II, match the gas evolved during each reaction.

Choose the correct answer from the options given below :

Which of the following has least tendency to liberate $\mathrm{H}_{2}$ from mineral acids?

In neutral or alkaline solution, $\mathrm{MnO}_{4}^{-}$ oxidises thiosulphate to :

Given below are two statements.

Statement I : Iron (III) catalyst, acidified $\mathrm{K}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}$ and neutral $\mathrm{KMnO}_{4}$ have the ability to oxidise $\mathrm{I}^{-}$ to $\mathrm{I}_{2}$ independently.

Statement II : Manganate ion is paramagnetic in nature and involves $\mathrm{p} \pi-\mathrm{p} \pi$ bonding.

In the light of the above statements, choose the correct answer from the options given below.

The total number of $\mathrm{Mn}=\mathrm{O}$ bonds in $\mathrm{Mn}_{2} \mathrm{O}_{7}$ is __________.

The dark purple colour of $\mathrm{KMnO}_{4}$ disappears in the titration with oxalic acid in acidic medium. The overall change in the oxidation number of manganese in the reaction is :

The electronic configuration of Pt (atomic number 78) is :

Which one of the lanthanoids given below is the most stable in divalent form?

[Given : Atomic no. Eu, 63; Sm, 62; Tm, 69; Tb, 65; Yb, 70; Dy, 66]

The most common oxidation state of Lanthanoid elements is +3. Which of the following is likely to deviate easily from +3 oxidation state?

The metal ion (in gaseous state) with lowest spin-only magnetic moment value is :

Cerium (IV) has a noble gas configuration. Which of the following is correct statement about it?

Among the following, which is the strongest oxidizing agent?

Metals generally melt at very high temperature. Amongst the following, the metal with the highest melting point will be :

Which of the following pair is not isoelectronic species?

(At. no. Sm, 62; Er, 68; Yb, 70; Lu, 71; Eu, 63; Tb, 65; Tm, 69)