Solid State: 220 NEET and JEE chemistry practice questions with solutions

Sample questions

5 of the 220 questions in this chapter. Answers and solutions open below each one.

Question 1 of 5, NEET levelClassification of solids and crystal lattices

Which of the following is a molecular solid?

ACopper
BDiamond
CDry ice ( $CO X_{2}$ , solid)
DSodium chloride

Answer and solution

Answer: C. Dry ice consists of discrete

CO X_{2}

molecules held by weak London forces, so it is a molecular solid. Diamond is a covalent network solid, NaCl is ionic and copper is metallic.

Question 2 of 5, NEET levelCubic unit cells: packing efficiency and density

The packing efficiency of a simple cubic unit cell is nearest to

A74%
B52.4%
C68%
D32%

Answer and solution

Answer: B. In simple cubic

a = 2 r

and

Z = 1

, so packing fraction

= \frac{\frac{4}{3} π r ^{3}}{( 2 r ) ^{3}} = \frac{π}{6} \approx 0.524

, i.e. 52.4%.

Question 3 of 5, NEET levelElectrical and magnetic properties of solids

The defect in which an ion leaves its lattice site and occupies an interstitial position is called

ASchottky defect
BF-centre
CFrenkel defect
DMetal excess defect due to anion vacancy

Answer and solution

Answer: C. A Frenkel defect is a dislocation defect: the (usually smaller cation) ion moves to an interstitial site, leaving a vacancy. It is seen in AgBr and ZnS and does not change the density.

Question 4 of 5, NEET levelClose packing, voids and radius ratio

Which stacking sequence of close-packed layers corresponds to cubic close packing (ccp)?

AABABAB...
BAABBAA...
CABCABC...
DABBABB...

Answer and solution

Answer: C. In ccp the third layer covers the octahedral voids of the second, so it differs from both A and B. The pattern is ABCABC..., whereas hcp is ABAB....

Question 5 of 5, NEET levelDefects in solids

Which effect does a Schottky defect have on the density of an ionic crystal?

AThe density decreases
BThe density increases
CThe density does not change
DThe density first rises, then falls

Answer and solution

Answer: A. A Schottky defect removes equal numbers of cations and anions from the lattice while the volume stays almost the same. The mass per unit volume therefore decreases.

How to use this chapter

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