Q 1 :

Which of the following acts as a strong reducing agent?
(Atomic number : Ce = 58, Eu = 63, Gd = 64, Lu = 71)                      [2024]

• ${\mathrm{Lu}}^{3+}$

   

• ${\mathrm{Ce}}^{4+}$

   

• ${\mathrm{Gd}}^{3+}$

   

• ${\mathrm{Eu}}^{2+}$

   

Q 2 :

The number of element from the following that do not belong to lanthanoids is

Eu, Cm, Er, Tb, Yb and Lu                                   [2024]

• 5

   

• 1

   

• 3

   

• 4

   

Q 3 :

The electronic configuration of Einsteinium is

(Given atomic number of Einsteinium = 99)                    [2024]

• $\left[\text{Rn}\right] 5f^{12} 6d^0 7s^2$

   

• $\left[\text{Rn}\right] 5f^{11} 6d^0 7s^2$

   

• $\left[\text{Rn}\right] 5f^{13} 6d^0 7s^2$

   

• $\left[\text{Rn}\right] 5f^{10} 6d^0 7s^2$

   

Q 4 :

Number of colourless lanthanoid ions among the following is _________ .         

${\text{Eu}}^{3+}, {\text{Lu}}^{3+}, {\text{Nd}}^{3+}, {\text{La}}^{3+}, {\text{Sm}}^{3+}$                          [2024]

Q 5 :

Diamagnetic Lanthanoid ions are:                        [2024]

• ${\text{Nd}}^{3+}$& ${\text{Eu}}^{3+}$

   

• ${\text{La}}^{3+}$& ${\text{Ce}}^{4+}$

   

• ${\text{Nd}}^{3+}$& ${\text{Ce}}^{4+}$

   

• ${\text{Lu}}^{3+}$& ${\text{Eu}}^{3+}$

   

Q 6 :

Lanthanoid ions with $4f^7$ configuration are:                 [2025]

(A)   ${\mathrm{Eu}}^{2+}$
(B)   ${\mathrm{Gd}}^{3+}$
(C)   ${\mathrm{Eu}}^{3+}$
(D)   ${\mathrm{Tb}}^{3+}$
(E)   ${\mathrm{Sm}}^{2+}$

• (A) and (B) only

   

• (B) and (C) only

   

• (A) and (D) only

   

• (B) and (E) only

   

Q 7 :

Which of the following ions is the strongest oxidizing agent?

(Atomic Number of Ce = 58, Eu = 63, Tb = 65, Lu = 71)                    [2025]

• ${\mathrm{Lu}}^{3+}$

   

• ${\mathrm{Ce}}^{3+}$

   

• ${\mathrm{Eu}}^{2+}$

   

• ${\mathrm{Tb}}^{4+}$

   

Q 8 :

Which one amongst the following are good oxidizing agents?

A. ${\mathrm{Sm}}^{2+}$  B. ${\mathrm{Ce}}^{2+}$

C. ${\mathrm{Ce}}^{4+}$  D. ${\mathrm{Tb}}^{4+}$

Choose the most appropriate answer from the options given below:                     [2023]

• D only

   

• C and D only

   

• C only

   

• A and B only

   

Q 9 :

${\mathrm{Nd}}^{2+}=$ ____________                    [2023]

• $4f^3$

   

• $4f^{4}6s^2$

   

• $4f^{2}6s^2$

   

• $4f^4$

   

Q 10 :

Which of the following elements have half-filled $f$-orbitals in their ground state?

(Given: atomic number Sm = 62; Eu = 63; Tb = 65; Gd = 64; Pm = 61)         [2023]

(A) Sm
(B) Eu
(C) Tb
(D) Gd
(E) Pm

Choose the correct answer from the options given below:

• A and B only

   

• C and D only

   

• B and D only

   

• A and E only

   

Q 11 :

Strong reducing and oxidizing agents among the following, respectively, are  [2023]

• ${\mathrm{Eu}}^{2+}$ and ${\mathrm{Ce}}^{4+}$

   

• ${\mathrm{Ce}}^{4+}$ and ${\mathrm{Eu}}^{2+}$

   

• ${\mathrm{Ce}}^{4+}$ and ${\mathrm{Tb}}^{4+}$

   

• ${\mathrm{Ce}}^{3+}$ and ${\mathrm{Ce}}^{4+}$

   

Q 12 :

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

Assertion A: $5f$ electrons can participate in bonding to a far greater extent than $4f$ electrons.

Reason R: $5f$ orbitals are not as buried as $4f$ orbitals.

In the light of the above statements, choose the correct answer from the options given below.  [2023]

• Both A and R are true but R is not the correct explanation of A

   

• A is true but R is false

   

• A is false but R is true

   

• Both A and R are true and R is the correct explanation of A

   

Q 13 :

The pair of lanthanides in which both elements have high third-ionization energy is:  [2023]

• Dy, Gd

   

• Lu, Yb

   

• Eu, Yb

   

• Eu, Gd

   

Q 14 :

The incorrect statements among the following is               [2025]

• ${\mathrm{PH}}_3$ shows lower proton affinity than ${\mathrm{NH}}_3$.

   

• ${\mathrm{PF}}_3$ exists but ${\mathrm{NF}}_5$ does not.

   

• ${\mathrm{NO}}_2$ can dimerise easily.

   

• ${\mathrm{SO}}_2$ can act as an oxidizing agent, but not as a reducing agent.

   

Q 15 :

Given below are two statements:                                       [2025]

Statement I: The N—N single bond is weaker and longer than that of P—P single bond.

Statement II: Compounds of group 15 elements in +3 oxidation states readily undergo disproportionation reactions.

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

• 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.

   

Q 16 :

Consider the following reactions,

$A+\underset{\text{Little amount}}{\mathrm{NaCl}}+{\mathrm{H}}_2{\mathrm{SO}}_4\to {\mathrm{CrO}}_2{\mathrm{Cl}}_2+\text{Side products}$

${\mathrm{CrO}}_2{\mathrm{Cl}}_2\left(\text{Vapour}\right)+\mathrm{NaOH}⟶B+\mathrm{NaCl}+{\mathrm{H}}_2\mathrm{O}$

$B+{\mathrm{H}}^{+}⟶C+{\mathrm{H}}_2\mathrm{O}$

The number of terminal 'O' present in the compound 'C' is ________                   [2025]

Q 17 :

Consider the following reactions.

${\mathrm{PbCl}}_2+{\mathrm{K}}_2{\mathrm{CrO}}_4\to \mathrm{A}+2\mathrm{KCl}$

$\text{(Hot solution)}$

$\mathrm{A}+\mathrm{NaOH}\rightleftharpoons \mathrm{B}+{\mathrm{Na}}_2{\mathrm{CrO}}_4$

${\mathrm{PbSO}}_4+4{\mathrm{CH}}_3{\mathrm{COONH}}_4\to {\left({\mathrm{NH}}_4\right)}_2{\mathrm{SO}}_4+\mathrm{X}$

In the above reactions, A, B, and X are respectively.    [2026]

• ${\mathrm{Na}}_2\left[\mathrm{Pb}{\left(\mathrm{OH}\right)}_2\right],{\mathrm{PbCrO}}_4\text{ and }{\left({\mathrm{NH}}_4\right)}_2\left[\mathrm{Pb}{\left({\mathrm{CH}}_3\mathrm{COO}\right)}_4\right]$

   

• ${\mathrm{PbCrO}}_4,{\mathrm{Na}}_2\left[\mathrm{Pb}{\left(\mathrm{OH}\right)}_4\right]\text{ and }\left[\mathrm{Pb}{\left({\mathrm{NH}}_3\right)}_4\right]{\mathrm{SO}}_4$

   

• ${\mathrm{Na}}_2\left[\mathrm{Pb}{\left(\mathrm{OH}\right)}_2\right],{\mathrm{PbCrO}}_4\text{ and }\left[\mathrm{Pb}{\left({\mathrm{NH}}_3\right)}_4\right]{\mathrm{SO}}_4$

   

• ${\mathrm{PbCrO}}_4,{\mathrm{Na}}_2\left[\mathrm{Pb}{\left(\mathrm{OH}\right)}_4\right]\text{ and }{\left({\mathrm{NH}}_4\right)}_2\left[\mathrm{Pb}{\left({\mathrm{CH}}_3\mathrm{COO}\right)}_4\right]$

   

Q 18 :

X and Y are the number of electrons involved, respectively, during the oxidation of ${\mathrm{I}}^{-}$ to ${\mathrm{I}}_2$ and ${\mathrm{S}}^{2-}$ to $\mathrm{S}$ by acidified ${\mathrm{K}}_2{\mathrm{Cr}}_2{\mathrm{O}}_7$. The value of $\mathrm{X}+\mathrm{Y}$ is ____ .        [2026]

Q 19 :

Consider the following reactions 

$\mathrm{NaCl}+{\mathrm{K}}_2{\mathrm{Cr}}_2{\mathrm{O}}_7+{\mathrm{H}}_2{\mathrm{SO}}_4\to \mathrm{A}+{\mathrm{KHSO}}_4+{\mathrm{NaHSO}}_4+{\mathrm{H}}_2\mathrm{O}$ 

$\mathrm{A}+\mathrm{NaOH}\to \mathrm{B}+\mathrm{NaCl}+{\mathrm{H}}_2\mathrm{O}$

$\mathrm{B}+{\mathrm{H}}_2{\mathrm{SO}}_4+{\mathrm{H}}_2{\mathrm{O}}_2\to \mathrm{C}+{\mathrm{Na}}_2{\mathrm{SO}}_4+{\mathrm{H}}_2\mathrm{O}$

In the product 'C', 'X' is the number of ${\mathrm{O}}_2^{2-}$ units, 'Y' is the total number oxygen atoms present and 'Z' is the oxidation state of Cr. The value of X + Y + Z is ______.    [2026]

Q 20 :

Among the following oxides of 3d elements, the number of mixed oxides are ____________.

${\mathrm{Ti}}_2{\mathrm{O}}_3,{\mathrm{V}}_2{\mathrm{O}}_4,{\mathrm{Cr}}_2{\mathrm{O}}_3,{\mathrm{Mn}}_3{\mathrm{O}}_4,{\mathrm{Fe}}_3{\mathrm{O}}_4,{\mathrm{Fe}}_2{\mathrm{O}}_3,{\mathrm{Co}}_3{\mathrm{O}}_4$        [2026]