Test: Previous Year Questions - D & F Block (Level 1)


13 Questions MCQ Test Chemistry Class 12 | Test: Previous Year Questions - D & F Block (Level 1)


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This mock test of Test: Previous Year Questions - D & F Block (Level 1) for Class 12 helps you for every Class 12 entrance exam. This contains 13 Multiple Choice Questions for Class 12 Test: Previous Year Questions - D & F Block (Level 1) (mcq) to study with solutions a complete question bank. The solved questions answers in this Test: Previous Year Questions - D & F Block (Level 1) quiz give you a good mix of easy questions and tough questions. Class 12 students definitely take this Test: Previous Year Questions - D & F Block (Level 1) exercise for a better result in the exam. You can find other Test: Previous Year Questions - D & F Block (Level 1) extra questions, long questions & short questions for Class 12 on EduRev as well by searching above.
QUESTION: 1

Arrange Ce3+, La3+, Pm3+, and Yb3+ in increasing order of their ionic radius – 

[AIEEE-02]

Solution:

The correct answer is Option A.
Atomic and ionic radii of Lanthanides decrease from La to Lu.
Their order of ionic radii:  
Yb3+ < Pm3+< Ce3+ < La3+

QUESTION: 2

What would happen when a solution of potassium chromate is treated with an excess of dilute nitric acid -

[AIEEE-03]

Solution:

The correct answer is Option B.
 
A solution of potassium chromate, when treated with an excess of dilute nitric acid doesn't oxidize nitric acid as N is already present in its maximum oxidation state (+5). The products formed are Cr2O72- and H2O.

QUESTION: 3

The radius of La3+ is 1.06 Å, which of the following given values will be closest to the radius of Lu3+ (At no. of Lu = 71, La = 57) –

[AIEEE-03]

Solution:

The correct answer is Option D.

Due to lanthanide contraction, the ionic radii of Ln3+ (lanthanide ions) decreases from La3+ to Lu3+. Thus the lowest value (here 0.85Å) is the ionic radius of Lu3+.

QUESTION: 4

Cerium (Z = 58) is an important member of the lanthanoids. Which of the following statement about cerium is incorrect -

[AIEEE-04]

Solution:

The incorrect statement about the Cerium is only a C option.
C: The +4 oxidation state of cerium is not known in solutions [ Incorrect ]
As +4 oxidation state is common for the Cerium.
The correct statement about the Cerium are as follows:
A: The common oxidation states of Cerium are +3, and +4.
B : The +3 oxidation state of the Cerium is more stable than the +4 oxidation state.
D: Cerium (IV) acts as an oxidising agent

QUESTION: 5

 Excess of KI reacts with CuSO4 solution and then Na2S2Osolution is added to it. Which of the statements is incorrect for this reaction -

[AIEEE-04]

Solution:

The correct answer is option B
It is given that an excess of KI reacts with CuSO4​ solution and then Na2​S2​O3​ is added to it. This is hypo test and reactions are as follows:
2CuSO4​ + 4KI → 2K2​SO4 ​+ 2CuI+I2
2Na2​S2​O3​ + I2​→ Na2​S4​O6 ​+ 2NaI
CuI2​ is not formed according to the following reaction.
2CuI2​(unstable) → 2CuI+I2
Hence, the statement in option B is incorrect.
 

QUESTION: 6

Calomel on reaction with NH4OH gives –

[AIEEE-04]

Solution:

The correct answer is option A
When calomel (Hg2​Cl2​) reacts with NH4​OH solution, the compound formed is [HgO.Hg(NH2​)Cl]. It is black in colour.
Hg2​Cl2​+2NH4​OH→[HgO.Hg(NH2​)Cl]↓+NH4​Cl+2H2​O

QUESTION: 7

The lanthanoid contraction is responsible for the fact that -

[AIEEE-05]

Solution:

The correct answer is Option C
Due to poor shielding effect of 4f electrons the nucleus experiences more effective nuclear charge and results in contraction which is known as lanthanide contraction. Due to lanthanide contraction 5th and 6th period transition series have approximately the same size. Therefore, lanthanide contraction is responsible for Zr and Hf having the same size.

QUESTION: 8

 Lanthanoid contraction is caused due to –

[AIEEE-06]

Solution:

The elements in the Lanthanide series are La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu.
In Lanthanides (Ce−Lu), the atomic and ionic radii decrease steadily. This steady decrease in atomic and ionic radii is known as Lanthanide Contraction. 
The contraction is due to the fact that f−orbitals are not capable of providing effective shielding for the valence electrons from the nuclear attraction.

QUESTION: 9

Identify the incorrect statement among the following -

[AIEEE-07]

Solution:

The correct answer is option D
4f and 5f belongs to different energy levels, hence the shielding effect on them is not the same. Shielding of 4f is more than 5f.
 

QUESTION: 10

The actinoids exhibits more number of oxidation states in general than the lanthanoids. This is because  

[AIEEE-07]

Solution:

The correct answer is option D
Lanthanoids primarily show three oxidation states (+2, +3, +4). Among these oxidation states, +3 state is the most common. Lanthanoids display a limited number of oxidation states because the energy difference between 4f, 5d and 6s orbitals is quite large. On the other hand, the energy difference between 5f, 6d and 7s orbitals is very less. Hence, actinoids display a large number of oxidation states.

QUESTION: 11

In context with the transition elements, which of the following statements is incorrect?

[AIEEE-09]

Solution:

The correct answer is option A
As oxidation state increases, electronegativity increases thus acidic characteristic increases not basic.
 

QUESTION: 12

Knowing that the Chemistry of lanthanoids (Ln) is dominated by its +3 oxidation state, which of the following statements is incorrect ?

[AIEEE-09]

Solution:

The correct answer is option  B
Ln(III) compounds are coloured due to the f−f transitions in the lanthanide but the colour is fainter as compared to the d−d transitions in transition metals.
 

QUESTION: 13

Iron exhibits + 2 and +3 oxidation states. Which of the following statements about iron is incorrect?

 [AIEEE-2012]

Solution:

The correct answer is Option D.

Ferrous oxide is more basic in nature than ferric oxide. Ferrous compounds are relatively more ionic than the corresponding ferric compounds. Ferrous compounds are less volatile than the corresponding ferric compounds as ferrous compounds are more ionic. 
 
But ferric compounds are more easily hydrolyzed than the corresponding ferrous compounds due to their more positive charge.