Solid State - Physical Chemistry - Chemistry Previous Year Questions

The correct option for axial distances and axial angles for hexagonal crystal system is

Iron crystalises in FCC with an edge length of 400 pm . If it contains $0.1 \%$ Schottky defects, calculate its approximate density

[Atomic weight of $\mathrm{Fe}=56 \mathrm{~g} / \mathrm{mol}$ ]

Identify the crystal system in which primitive unit cell has edge lengths $a=b=200 \mathrm{pm}$ and $c=300 \mathrm{pm}$ and all axial angles are same

A compound is formed by elements $A, B$ and O . Atoms of oxygen form ccp lattice. Atoms of $A$ (cation) occupy $\frac{1}{8}$ th of tetrahedral voids and atoms of $B$ (cation) occupy half of octahedral voids. What is the molecular formula of the compound?

A body centred cubic lattice is made up of two different types of atoms $X$ and $Y$. Atom $X$ occupies the body centre and atoms $Y$ occupy the corner positions. One of the corners is left unoccupied per unit cell. The empirical formula of it is

In the structure of a solid, W atoms are located at the cube corners of the unit cell, O atoms are located at the cube edges and Na atoms at the cube centres. The formula of the compound is

The formula of a metal oxide is $M_{0.96} \mathrm{O}_1$. The fractions of metal that exists as $M^{3+}$ and $M^{2+}$ ions in that oxide are respectively

In a bcc lattice having the edge length of 200 pm , the cation has the radius of 70 pm . The radius ratio of $\frac{r^{+}}{r^{-}}$is (Given, $\sqrt{2}=1.4, \sqrt{3}=1.7$ and $\sqrt{6}=2.4$ )

Copper crystallises in ccp arrangement and accepted value of metal ion radius was found to be $1.14 \mathop {\rm{A}}\limits^{\rm{o}}$. Calculate the density of copper in grams per cubic centimetre. (Atomic weight of copper is 64 , $N_A=6 \times 10^{23}$ )

If the length of the body diagonal of a FCC unit cell is $x \mathop {\rm{A}}\limits^{\rm{o}}$, the distance between two octahedral voids in the cell in $\mathop {\rm{A}}\limits^{\rm{o}}$ is

The number of nearest neighbours in a bcc unit cell is

A solid has a structure in which ' W ' atoms are located at the corners of a cubic lattice, oxygen atoms at the edge centre and

Na atom at the body centre. The formula of the compound is

KBr has rock salt type structural arrangements and has a density of

$3.70 \mathrm{~g} / \mathrm{cm}^3$. The edge length of the unit cell is approximately [molecular weight of $\mathrm{KBr}=120 \mathrm{~g} / \mathrm{mol}$ ]

Assertion (A) Graphite is used as a dry lubricant in machines which run at high temperatures.

Reason ( $\mathbf{R}$ ) The layers of graphite slip one over the other when pressure is applied.

The correct option among the following is