Select the correct option based on statements below:

The coordination number of a square close-packed structure in two dimensions is -

1. 2

2. 3

3. 4

4. 6

An example of amorphous solid among the following is -

1. Graphite (C)

2. Quartz glass (SiO₂)

3. Chrome alum

4. Silicon carbide (SiC)

 The pair having only molecular solids among the following is -

1. Brass and SiC

2. Ammonium phosphate (NH₄)₃PO₄

3. SiC and plastic 

4. Tetra phosphorus decaoxide (P₄O₁₀) and I₂

The correct order of the packing efficiency in different types of unit cells is-

1.  Fcc < Bcc < Simple cubic

2.  Fcc > Bcc > Simple cubic

3.  Fcc < Bcc > Simple cubic

4.  Bcc < Fcc > Simple cubic

The most efficient packing is present in -

1. HCP and BCC

2. HCP and CCP

3. BCC and CCP

4. BCC and Simple cubic cell

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

The formula of nickel oxide with metal deficiency defect in its crystal is $N{i}_{0.98}O$. The crystal contains ${\mathrm{Ni}}^{2+} \mathrm{and} {\mathrm{Ni}}^{3+}$ ions. The fraction of nickel existing as $N{i}^{2+}$ ions in the crystal is-

1. 0.96

2. 0.04

3. 0.50

4. 0.31

The anions (A) form hexagonal closest packing and atoms (C) occupy only 2/3 of octahedral voids in it. The general formula of the compound is-
1. CA
2. CA₂
3. C₂A₃
4. C₃A₂