Select the correct option based on statements below:

Assertion (A):	Due to Frenkel defect, the density of the crystalline solid decreases.
Reason (R):	In Frenkel defect cation and anion leave the crystal.

 

1.	Both (A) and (R) are true and (R) is the correct explanation of (A).
2.	Both (A) and (R) are true but (R) is not the correct explanation of (A).
3.	(A) is true but (R) is false.
4.	Both (A) and (R) are false.

The crystal with a metal deficiency defect is - 

1. NaCl 

2. FeO

3. ZnO 

4. KCl

The radius ratio (r⁺/r^-) of KF is 0.98. The structure of KF is similar to

1. NaCl

2. CsCl

3. ZnS

4. Both 1 and 2

A compound formed by elements A and B crystallizes in cubic structure where A atoms are at the corners or a cube and B atoms are at the face centre. The formula of the compound is :

1. AB

2. AB₂

3. AB₃

4. AB₄

ln NaCl, the chloride ions occupy the space in a Fashion of 

1. BCC

2. FCC

3. Both 

4. None of the above 

A compound formed by elements A and B crystallizes in cubic structure where A atoms are at the corners or a cube and B atoms are at the face centre. The formula of the compound is :

(1) AB

(2) AB₂

(3) AB₃

(4) AB₄

An element has a body-centered cubic (BCC) structure with a cell edge of 288 pm. The atomic radius is:

1. $\frac{\sqrt{2}}{4}\times 288$ pm

2. $\frac{4}{\sqrt{3}}\times 288$ pm

3. $\frac{4}{\sqrt{2}}\times 288$ pm

4. $\frac{\sqrt{3}}{4}\times 288$ pm

NaCl sometimes appear yellow in colour because of :

1. Reaction with air.

2. Metal excess defect due to anionic vacancies.

3. Metal deficiency defect due to cation vacancies.

4. Schottky defect.

FeO(s) is not formed in stoichiometric composition because : 

1. Three Fe²⁺ ions are replaced by two Fe³⁺ ions.

2. Two Fe²⁺ ions are replaced by three Fe³⁺ ions.

3. Three Fe²⁺ ions are replaced by three Fe³⁺ ions.

4. Two Fe²⁺ ions are replaced by two Fe³⁺ ions.

White ZnO (s) becomes yellow upon heating due to shifting of :

1. Protons to interstitial sites and F-centres.

2. Electrons to interstitial sites and F-centres.

3. Photons to interstitial sites and F-centres.

4. Neutrons to interstitial sites and F-centres.