Solid State · Chemistry · TS EAMCET

In bcc lattice containing $X$ and $Y$ type of atoms, $X$ type of atoms are present at the corners and $Y$ type of atoms are present at the centers. In its unit cell, if three atoms are missing in the corners, the formula of the compound is

The molecular formula of a crystal is $A B_{2} \mathrm{O}_{4}$. Oxygen atoms form ccp lattice. Atoms of $A$ occupy $x \%$ of tetrahedral voids and atoms of $B$ occupy $y \%$ of octahedral voids. $x$ and $y$ are respectively

An element with molar mass $2.7 \times 10^{-2} \mathrm{~kg} \mathrm{~mol}^{-1}$ forms a cubic unit cell with edge length of 405 pm . If its density is $2.7 \times 10^3 \mathrm{~kg} \mathrm{~m}^{-3}$, the number of atoms present in one unit cell of it is (Given; $N_A=6.023 \times 10^{23} \mathrm{~mol}^{-1}$ )

Identify the correct statement about the crystal defects in solids.

The molecular formula of a compound is $A B_2 \mathrm{O}_4$. Atoms of $O$ form ccp lattice. Atoms of $A$ (cation) occupy $\frac{1}{8}$ th of tetrahedral voids. Atoms of $B$ (cation) occupy a fraction of octahedral voids. What is the fraction of vacant octahedral voids?

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

At $T(\mathrm{~K})$, copper (atomic mass $=63.5 \mathrm{u}$ ) has fce structure with an edge length of $x \AA$. The density of copper (in $\mathrm{g} \mathrm{cm}^{-3}$ ) at that temperature approximately is $\left(N_A=6.0 \times 10^{23} \mathrm{~mol}^{-1}\right)$