Solid State NEET Questions: Important Solid State Questions For NEET

NEET Solid State Previous Year Question Analysis

Analysing the NEET previous year’s papers is very important for identifying exam trends, important topics, and question patterns. Understanding the frequency of questions, chapter-wise distribution, and difficulty levels of the past questions can provide a clear insight for focused preparation.

NEET Solid State Chapter-Wise Question Distribution (2020-2024)

Solid State Previous Year Questions in NEET Exam

1. Calculate the density of a solid if the atomic solid is crystallised in body centered cubic lattice, the inner surface of the atom at adjacent corners are separated by 60.3 pm, and the atomic mass of A is.

Option 1) 1.86

Option 2) 1.9

Option 3) 1.3

Option 4) 2.4

Solution:

In a BCC lattice, atoms touch along the body diagonal.
So, 4r=3a

Here, the distance between inner surfaces of adjacent corner atoms = a−2r=60.3pm

From the relation 4r=3a,
r=34a

So, a−2(34a)=60.3
a(1−32)=60.3
a=60.31−32pm
a≈352pm=3.52×10−8cm

Volume of unit cell = a3=(3.52×10−8)3cm3
a3≈4.37×10−23cm3

In BCC, the number of atoms per unit cell = 2

Mass of unit cell = 2MNA, where M=50g mol−1 (assumed from data), NA=6.022×1023

Density=Mass of unit cellVolume of unit cell

ρ=2MNA⋅a3

Substituting values:
ρ=2×506.022×1023×4.37×10−23

ρ≈1.86g cm−3

\textbf{Correct Option: 1) 1.86}

Hence, the answer is option (2).

Ques: Calculate the number of unit cells in the atom that lies on the surface of a cubic crystal that is 2.0cm in length.

1) 0.18×10−3

2) 1.24×10−2

3) 1.84×10−1

4) 0.86×10−2

0.86×10−2

Solution -

In a cubic crystal, we use the relation:

4R=3a

So,

a=22.17pm=1.09×10−9m

Now, volume of the cube = (2.0cm)3=(2.0×10−2m)3

=8.0×10−6m3

Volume of one unit cell = a3=(1.09×10−9)3m3

=1.29×10−27m3

Number of unit cells = Volume of crystalVolume of one unit cell

=8.0×10−61.29×10−27

=0.18×10−3

AC:∴4R=3aa=22.17pm=10.9×10−3 m3(2.0 cm)3=(20−2)3=20−6 m3 No. of unit cell =20−6 m310.9×10−3 m3=0.18×10−Hence, the answer is option (1).

3. Ammonium chloride crystallizes in a body-centred cubic lattice with an edge length of a unit cell of 480 pm. If the size of the chloride ion is 240 pm, the size of the ammonium ion would be

Option 1) 180.6

Option 2) 182.4

Option 3) 175.2

Option 4) 166.9

Solution -

For a body-centred cubic lattice of NH4Cl, we know that:

32a=rNH4++rCl−

Substitute values:
32×480=rNH4++240

415.7=rNH4++240

rNH4+=415.7−240

rNH4+=175.7pm

Hence, the size of the ammonium ion ≈175.2pm.

3a2=r++r−3×4802−r++240415.2−240=r+175.2=r+

The answer is option (3).

4. Which of the following statements is not true for the crystal structure of cesium chloride (CsCl)?

Option 1) CsCl has a cubic structure.

Option 2) Cs+ and Cl- ions are arranged in a face-centred cubic lattice.

Option 3) Cs+ and Cl- ions have a coordination number of 8 and 6, respectively.

Option 4) The Cs+ ions are located at the corners of the cube and Cl- ions are at the center of the cube.

Solution - CsCl is an example of a simple cubic crystal lattice, not a face-centred cubic lattice as stated in option
2. In a simple cubic lattice, the unit cell consists of a cube with lattice points located at the corners of the cube. Each lattice point represents one Cs+ion. Additionally, there is one Cl−ion located at the centre of the cube.

In CsCl, each Cs+ion is surrounded by 8Cl−ions arranged at the corners of a cube around it, resulting in a coordination number of 8 for the Cs+ion. On the other hand, each Cl−ion is surrounded by 6Cs+ions arranged at the corners of an octahedron around it, resulting in a coordination number of 6 for the Cl−ion. This is stated in option 3.

Therefore, the correct statement regarding the location of Cs+and Cl−ions in the CsCl crystal structure is that Cs+ions are located at the corners of the cube and Cl−ions are located at the centre of the cube.

Option 4) incorrectly describes the location of the Cl−ion in the CsCl unit cell.

Hence, the answer is option (4).

5. Which of the following ionic solids has the highest packing efficiency?

Option 1) NaCl

Option 2) CsCl

Option 3) ZnS

Option 4) FeOCaF2

Solution - The correct answer is an option (c) ZnS,also known as zinc sulfide, has the highest packing efficiency among the given options. ZnS has a zincblende structure, which has a cubic close-packed (CCP) arrangement of both cations (Zn2+) and anions (S2−)in which they occupy alternate positions. This arrangement results in the highest packing efficiency of approximately 74%, which is the maximum possible packing efficiency for ionic solids. NaCl (sodium chloride), CsCl′ (cesium chloride), and CaF2 (calcium fluoride) have different crystal structures with lower packing efficiencies compared to ZnS. Hence, the correct answer is option (c) ZnS.

Hence, the answer is the option (3).

6. A crystal has a face-centered cubic (FCC) structure with an edge length of 4/AA. The radius of the atoms in the crystal is 1/AA. What is the packing efficiency of the FCC structure?

Option 1) 33.3%

Option 2) 48.6%

Option 3) 52.4%

Option 4) 74.0%

Solution - The packing efficiency of a face-centered cubic (FCC) structure is 74%. This is a characteristic property of FCC structures, where atoms are arranged in a closely packed manner with atoms located at the corners and the center of each face of the unit cell.

Hence, the answer is the option (4).

7. Assertion: The body-centred cubic lattice has a higher packing efficiency than the simple cubic lattice.

Reasoning: In the body-centred cubic lattice, the atoms are located at the corners and at the centre of the unit cell, which allows for a more efficient packing than the simple cubic lattice.

Option 1) Both assertion and reasoning are true, and the reasoning is the correct explanation of the assertion.

Option 2) Both assertion and reasoning are true, but the reasoning is not the correct explanation of the assertion.

Option 3) The assertion is true, but the reasoning is false.

Option 4) Both assertion and reasoning are false.

Solution - The assertion that the body-centred cubic lattice has a higher packing efficiency than the simple cubic lattice is true. In the body-centred cubic lattice, the constituent particles are located at the corners and the centre of the unit cell. This allows for a more efficient packing than the simple cubic lattice, where the particles are located only at the corners of the unit cell.

The reasoning that the atoms are located at the corners and the centre of the unit cell in the body-centred cubic lattice, allowing for a more efficient packing than the simple cubic lattice, is also correct. The body-centred cubic lattice has a packing efficiency of 68%, while the simple cubic lattice has a packing efficiency of only 52%.

Therefore, both the assertion and reasoning are true, and the reasoning correctly explains the assertion.

Hence, the answer is option (1).

How to Prepare for Solid State NEET Questions?

Solid State is a scoring chapter in the NEET Chemistry syllabus, and with the right preparation strategy, students can easily secure full marks from this topic. Focus on concepts, formulas, and repeated practice of questions to master it effectively.

• Focus on crystal lattice types and unit cell dimensions.
• Revise packing efficiency, coordination number, and radius ratio rules.
• Practice numerical questions on density and edge length.
• Learn different types of voids and defects (Schottky, Frenkel, metal excess).
• Go through the previous year's NEET questions for trend analysis.
• Make short notes and formula sheets for quick revision before exams.