jee main chemistry important questions | d And f-Block Elements jee main questions FREE

Q 1 :

When a salt treated with sodium hydroxide solution it gives gas X on passing gas X through reagent Y a brown coloured precipitate is formed. X and Y respectively, are [2025]

$X = {NH}_{4} Cl$ and $Y = KOH$
$X = {NH}_{3}$ and $Y = HgO$
$X = {NH}_{3}$ and $Y = K_{2} {HgI}_{4} + KOH$
$X = HCl$ and $Y = {NH}_{4} Cl$

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(3)

Q 2 :

The group 14 elements A and B have the first ionisation enthalpy values of 708 and 715 kJ ${mol}^{- 1}$ respectively. The above values are lowest among their group members. The nature of their ions $A^{2 +}$ and $B^{4 +}$ respectively is [2025]

both reducing
both oxidising
oxidising and reducing
reducing and oxidising

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(4)

Q 3 :

The correct statements from the following are

(A) ${Tl}^{3 +}$ is a powerful oxidising agent.

(B) ${Al}^{3 +}$ does not get reduced easily

(C) Both ${Al}^{3 +}$ and ${Tl}^{3 +}$ are very stable in solution.

(D) ${Tl}^{+}$ is more stable than ${Tl}^{3 +}$ .

(E) ${Al}^{3 +}$ and ${Tl}^{+}$ are highly stable.

Choose the correct answer from the options given below : [2025]

(A), (B), (C), (D) and (E)
(A), (C) and (D) only
(A), (B), (D) and (E) only
(B), (D) and (E) only

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(3)

Q 4 :

Given below are two statements. [2025]

Statement I : $H_{2} Se$ is more acidic than $H_{2} Te$ .

Statement II : $H_{2} Se$ has higher bond enthalpy for dissociation than $H_{2} Te$ .

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

Both Statement I and Statement II are true.
Statement I is false but Statement II is true.
Both Statement I and Statement II are false.
Statement I is true but Statement II is false.

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(2)

Q 5 :

A first row transition metal (M) does not liberate $H_{2}$ gas from dilute $HCl$ . 1 mol of aqueous solution of ${MSO}_{4}$ is treated with excess of aqueous $KCN$ and then $H_{2} S (g)$ is passed through the solution. The amount of $MS$ (metal sulphide) formed from the above reaction is _______ mol. [2026]

0
1
2
3

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(1)

$Cu \overset{dil. HCl}{\to} no reaction$

${CuSO}_{4} \overset{KCN}{\to} \underset{perfect complex}{{[Cu {(CN)}_{4}]}^{3 -}} \overset{H_{2} S}{\to} no sulphide ppt$

Q 6 :

Consider the transition metal ions ${Mn}^{3 +}$ , ${Cr}^{3 +}$ , ${Fe}^{3 +}$ and ${Co}^{3 +}$ and all form low spin octahedral complexes. The correct decreasing order of unpaired electrons in their respective $d$ -orbitals of the complexes is [2026]

${Cr}^{3 +} > {Mn}^{3 +} > {Fe}^{3 +} > {Co}^{3 +}$
${Mn}^{3 +} > {Fe}^{3 +} > {Co}^{3 +} > {Cr}^{3 +}$
${Fe}^{3 +} > {Co}^{3 +} > {Mn}^{3 +} > {Cr}^{3 +}$
${Cr}^{3 +} > {Fe}^{3 +} > {Co}^{3 +} > {Mn}^{3 +}$

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(1)

${Co}^{3 +} \to 3 d^{6} \Rightarrow t_{2 g}^{2, 2, 2} e_{g}^{0, 0}, unpaired electron = 0$

${Fe}^{3 +} \to 3 d^{5} \Rightarrow t_{2 g}^{2, 2, 1} e_{g}^{0, 0}, unpaired electron = 1$

${Cr}^{3 +} \to 3 d^{3} \Rightarrow t_{2 g}^{1, 1, 1} e_{g}^{0, 0}, unpaired electron = 3$

${Mn}^{3 +} \to 3 d^{4} \Rightarrow t_{2 g}^{2, 1, 1} e_{g}^{0, 0}, unpaired electron = 2$

Q 7 :

Consider the following statements about manganate and permanganate ions. Identify the correct statements.

A. The geometry of both manganate and permanganate ions is tetrahedral.
B. The oxidation states of Mn in manganate and permanganate are +7 and +6, respectively.
C. Oxidation of Mn(II) salt by peroxodisulphate gives manganate ion as the final product.
D. Manganate ion is paramagnetic and permanganate ion is diamagnetic.
E. Acidified permanganate ion reduces oxalate, nitrite and iodide ions.

Choose the correct answer from the options given below: [2026]

A, D and E Only
A and D Only
A, B and C Only
A, C and D Only

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(2)

$Manganate ion \to {MnO}_{4}^{2 -}$

$Permanganate ion \to {MnO}_{4}^{-}$

(A) Both are tetrahedral ( $d^{3} s$ Hybridisation)

(B) ${MnO}_{4}^{-}$ (+7 oxidation state)

${MnO}_{4}^{2 -}$ (+6 oxidation state)

(C) ${Mn}^{2 +} + S_{2} O_{8}^{2 -} \to {MnO}_{4}^{-}$ (Permanganate ion)

(D) ${MnO}_{4}^{-} \to$ Diamagnetic

${MnO}_{4}^{2 -} \to$ Paramagnetic

(E) It is oxidising agent

Q 8 :

200 cc of $x \times 10^{- 3}$ M potassium dichromate is required to oxidise 750 cc of 0.6 M Mohr’s salt solution in acidic medium.

Here x = ______. [2026]

(375)

$Number of equivalents of {Cr}_{2} O_{7}^{2 -} = Number of equivalents of Mohr's salt$

$200 \times x \times 10^{- 3} \times 6 = 750 \times 0.6 \times 1$

$x = 375$

Q 9 :

On heating a mixture of common salt and $K_{2} {Cr}_{2} O_{7}$ in equal amount along with concentrated $H_{2} {SO}_{4}$ 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: [2026]

$C r_{2} O_{2} C l_{2} and + 6$
$C r O_{2} C l_{2} and + 5$
$C r O_{2} C l_{2} and + 6$
$C r_{2} O_{2} C l_{2} and + 3$

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(3)

$4 NaCl + K_{2} {Cr}_{2} O_{7} + 6 H_{2} {SO}_{4}$

$⟶ 2 {KHSO}_{4} + \underset{(Chromyl chloride)}{2 {CrO}_{2} {Cl}_{2}} + 4 {NaHSO}_{4} + 3 H_{2} O$

$In Chromyl chloride Cr is in + 6 oxidation state.$

Q 10 :

Aqueous HCl reacts with ${MnO}_{2} {(s) to form MnCl}_{2} {(aq), Cl}_{2} (g) and H₂O (l)$ . What is the weight (in g) of ${Cl}_{2}$ liberated when 8.7 g of ${MnO}_{2} (s)$ is reacted with excess aqueous HCl solution ?

(Given Molar mass in g ${mol}^{- 1}$ Mn = 55, Cl = 35.5, O = 16, H = 1) [2026]

14.2
71
7.1
21.3

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(3)

${MnO}_{2} + 4 HCl \to {MnCl}_{2} + {Cl}_{2} + 2 H_{2} O$

$\frac{8.7}{87}$ Excess

$= 0.1 mole$ $0.1 mole$

$Wt. of C l_{2} obtained = 0.1 \times 71 = 7.1 g$

Q 11 :

Given below are some of the statements about Mn and ${Mn}_{2} O_{7} .$ Identify the correct statements.

A. Mn forms the oxide ${Mn}_{2} O_{7}$ , 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. ${Mn}_{2} O_{7}$ is an ionic oxide.
D. The structure of ${Mn}_{2} O_{7}$ consists of one bridged oxygen.

Choose the correct answer from the options given below : [2026]

A, C and D Only
A, B, C and D
A, B and C Only
A, B and D Only

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(4)

${Mn}_{2} O_{7}$ : Mn in +7 oxidation state.

Q 12 :

Identify the metal ions among ${Co}^{2 +}, {Ni}^{2 +}, {Fe}^{2 +}, V^{3 +} and {Ti}^{2 +}$ having a spin-only magnetic moment value more than 3.0 BM. The sum of unpaired electrons present in the high spin octahedral complexes formed by those metal ions is____________. [2026]

(7)

$V^{3 +} = {(Ar)}_{18} 3 d^{2}$

${Ti}^{2 +} = {(Ar)}_{18} 3 d^{2}$

${Ni}^{2 +} = {(Ar)}_{18} 3 d^{8}$

${Fe}^{2 +} = {(Ar)}_{18} 3 d^{6}$

${Co}^{2 +} = {(Ar)}_{18} 3 d^{7}$

${Only for Fe}^{2 +} {and Co}^{2 +}, μ is more than 3.0 B.M.$

$∴$ Number of unpaired electrons = 4 + 3 = 7

Q 13 :

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 : [2026]

Both Statement I and Statement II are false
Both Statement I and Statement II are true
Statement I is true but Statement II is false
Statement I is false but Statement II is true

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(3)

$Cr = (Ar) 3 d^{5} 4 s^{1}$

$Mn = (Ar) 3 d^{5} 4 s^{2}$

$I E_{1} (Cr) < I E_{1} (Mn)$

$I E_{2} (Cr) > I E_{2} (Mn)$

$I E_{3} (Cr) < I E_{3} (Mn)$

Q 14 :

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.

$[[{Sc}^{3 +}, {Ti}^{3 +}]], [[{Mn}^{2 +}, {Cr}^{2 +}]], [[{Cu}^{2 +}, {Zn}^{2 +}]] and [[{Ni}^{2 +}, {Ti}^{4 +}]]$

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

In the light of the above statements, choose the correct answer from the options given below. [2026]

Statement I is true but Statement II is false
Both Statement I and Statement II are false
Both Statement I and Statement II are true
Statement I is false but Statement II is true

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(2)

${Sc}^{3 +}, {Ti}^{4 +} {and Zn}^{2 +} are colourless$

${Th}^{4 +} cannot act as a reducing agent.$

Topic Question Set

Q 1 :

When a salt treated with sodium hydroxide solution it gives gas X on passing gas X through reagent Y a brown coloured precipitate is formed. X and Y respectively, are [2025]

(3)

Q 2 :

The group 14 elements A and B have the first ionisation enthalpy values of 708 and 715 kJ ${mol}^{- 1}$ respectively. The above values are lowest among their group members. The nature of their ions $A^{2 +}$ and $B^{4 +}$ respectively is [2025]

(4)

(3)

Q 4 :

Given below are two statements. [2025]

Statement I : $H_{2} Se$ is more acidic than $H_{2} Te$ .

Statement II : $H_{2} Se$ has higher bond enthalpy for dissociation than $H_{2} Te$ .

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

(2)

Q 6 :

Consider the transition metal ions ${Mn}^{3 +}$ , ${Cr}^{3 +}$ , ${Fe}^{3 +}$ and ${Co}^{3 +}$ and all form low spin octahedral complexes. The correct decreasing order of unpaired electrons in their respective $d$ -orbitals of the complexes is [2026]

Q 8 :

200 cc of $x \times 10^{- 3}$ M potassium dichromate is required to oxidise 750 cc of 0.6 M Mohr’s salt solution in acidic medium.

Here x = ______. [2026]

Q 9 :

On heating a mixture of common salt and $K_{2} {Cr}_{2} O_{7}$ in equal amount along with concentrated $H_{2} {SO}_{4}$ 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: [2026]

Q 12 :

Identify the metal ions among ${Co}^{2 +}, {Ni}^{2 +}, {Fe}^{2 +}, V^{3 +} and {Ti}^{2 +}$ having a spin-only magnetic moment value more than 3.0 BM. The sum of unpaired electrons present in the high spin octahedral complexes formed by those metal ions is____________. [2026]

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Topic Question Set

Q 1 : When a salt treated with sodium hydroxide solution it gives gas X on passing gas X through reagent Y a brown coloured precipitate is formed. X and Y respectively, are [2025]

(3)

Q 2 : The group 14 elements A and B have the first ionisation enthalpy values of 708 and 715 kJ mol-1 respectively. The above values are lowest among their group members. The nature of their ions A2+ and B4+ respectively is [2025]

(4)

(3)

Q 4 : Given below are two statements. [2025] Statement I : H2Se is more acidic than H2Te. Statement II : H2Se has higher bond enthalpy for dissociation than H2Te. In the light of the above statements, choose the correct answer from the options given below:

(2)

Q 5 : A first row transition metal (M) does not liberate H2 gas from dilute HCl. 1 mol of aqueous solution of MSO4 is treated with excess of aqueous KCN and then H2S(g) is passed through the solution. The amount of MS (metal sulphide) formed from the above reaction is _______ mol. [2026]

Q 6 : Consider the transition metal ions Mn3+, Cr3+, Fe3+ and Co3+ and all form low spin octahedral complexes. The correct decreasing order of unpaired electrons in their respective d-orbitals of the complexes is [2026]

Q 8 : 200 cc of x×10-3 M potassium dichromate is required to oxidise 750 cc of 0.6 M Mohr’s salt solution in acidic medium. Here x = ______. [2026]

Q 9 : On heating a mixture of common salt and K2Cr2O7 in equal amount along with concentrated H2SO4 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: [2026]

Q 10 : Aqueous HCl reacts with MnO2(s) to form MnCl2(aq), Cl2(g) and H₂O(l). What is the weight (in g) of Cl2 liberated when 8.7 g of MnO2(s) is reacted with excess aqueous HCl solution ? (Given Molar mass in g mol-1 Mn = 55, Cl = 35.5, O = 16, H = 1) [2026]

Q 12 : Identify the metal ions among Co2+, Ni2+, Fe2+, V3+ and Ti2+ having a spin-only magnetic moment value more than 3.0 BM. The sum of unpaired electrons present in the high spin octahedral complexes formed by those metal ions is____________. [2026]

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Q 1 :

When a salt treated with sodium hydroxide solution it gives gas X on passing gas X through reagent Y a brown coloured precipitate is formed. X and Y respectively, are [2025]

Q 2 :

The group 14 elements A and B have the first ionisation enthalpy values of 708 and 715 kJ ${mol}^{- 1}$ respectively. The above values are lowest among their group members. The nature of their ions $A^{2 +}$ and $B^{4 +}$ respectively is [2025]

Q 4 :

Given below are two statements. [2025]

Statement I : $H_{2} Se$ is more acidic than $H_{2} Te$ .

Statement II : $H_{2} Se$ has higher bond enthalpy for dissociation than $H_{2} Te$ .

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

Q 6 :

Consider the transition metal ions ${Mn}^{3 +}$ , ${Cr}^{3 +}$ , ${Fe}^{3 +}$ and ${Co}^{3 +}$ and all form low spin octahedral complexes. The correct decreasing order of unpaired electrons in their respective $d$ -orbitals of the complexes is [2026]

Q 8 :

200 cc of $x \times 10^{- 3}$ M potassium dichromate is required to oxidise 750 cc of 0.6 M Mohr’s salt solution in acidic medium.

Here x = ______. [2026]

Q 9 :

On heating a mixture of common salt and $K_{2} {Cr}_{2} O_{7}$ in equal amount along with concentrated $H_{2} {SO}_{4}$ 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: [2026]

Q 12 :

Identify the metal ions among ${Co}^{2 +}, {Ni}^{2 +}, {Fe}^{2 +}, V^{3 +} and {Ti}^{2 +}$ having a spin-only magnetic moment value more than 3.0 BM. The sum of unpaired electrons present in the high spin octahedral complexes formed by those metal ions is____________. [2026]