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

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

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

The crystal with a metal deficiency defect is - 

1. NaCl 

2. FeO

3. ZnO 

4. KCl

Select the correct option based on statements below:

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.

The electrical conductivity of semiconductors increases with a rise in temperature because: