Question 1 :
A solid has three types of atoms $X,\ Y$ and $Z$. $X$ forms an $FCC$ lattice with $Y$ atoms occupying all the tetrahedral voids and $Z$ atoms occupying half of the octahedral voids. The formula of the solid is

Question 2 :
Aluminium crystallizes in a cubic close packed structure. Its metallic radius is $125$ pm. The edge length (in pm) of the unit cell and number of unit cells per cc of aluminium, respectively, are :

Question 3 :
An alloy of $Cu, Ag$ and $Au$ is found to have copper constituting fcc lattice. If silver atoms occupy the edge-centers and gold is present at body-center, the alloy has the formula _______.

Question 4 :
Assertion: It occupies certain holes of this type but not the other holes of the same type? Reason: The proximity of two cations $(A^{2+ }\,\,and \,\,B^{4+})$ would be electrostatically unfavourable.

Question 5 :
If in a cubic cell, atoms $A$ present at all corners and atoms $B$ at the center of each face. What will be the molecular formula of the compound, if all the atoms present in one body diagonal are replaced by atom $C$?<br>

Question 6 :
A binary solid has a primitive cubical structure with $B^-$ ions constituting the lattice points and $A^+$ ions occupying 25% of its tetrahedral holes. The molecular formula of the crystal is:<br/>

Question 7 :
An element crystalline in body centered cubic lattice has an edge of 500 pm. If its density is 4 g $cm^{-3}$, the atomic mass of the element (in g $mol^{-1}$) is:&#160;<div>(consider $N_A=6\times10^{23}$)&#160;<br/></div>

Question 9 :
Gold is plated with rhodium to give a base for&#160;mounting diamonds in modern jewellery. The&#160;rhodium-gold alloy consists of gold atoms in fcc&#160;structure with half the face centers being replaced&#160;by rhodium atoms. Formula of this alloy is :<br/>

Question 10 :
A solid is formed and it has three types of atoms X, Y, Z. X forms an FCC lattice with Y atoms occupying one-forth of tetrahedral viods and Z atoms occupying half of the octahedral voids. The formula of the solid is?

Question 11 :
$CsCl$ crystallizes in a cubic lattice that has a $Cl^-$ at each corner and $Cs^+$ at the centre of the unit cell. If $(r_{Cs^+})=1.69\overset{o}{A}$ and $(r_{Cl^-})=1.81\overset{o}{A}$, what is the value of edge length a of the cube?<br>

Question 12 :
A crystal is made up of particles A, B, and C, A forms fcc packing, B occupies all octahedral voids and C occupies all tetrahedral voids. If all the particles along one body diagonal are removed, then the formula of the crystal would be:

Question 14 :
The density and edge length values for a crystallise elemens with $fcc$ lattice are $10 g$ $cm^{-3}$ and 400 pm, respectively. The number of unit cell in $32 g$ of this crystal is:

Question 15 :
Iron crystallizes in several modifications, At about $910^o$C, the body centred $\alpha$-form undergoes transition to the face centred cubic $\gamma$-form. Assuming that the distance between nearest neighbours is same in the two forms at the transition temperature. Calculate the ratio of density of $\gamma$-iron to that of $\alpha$-iron at the transition temperature.

Question 16 :
A compound is formed by cation $C$ and anion $A$. The anions form hexagonal close packed (hcp) lattice and the cations occupy $75\%$ of octahedral voids. The formula of the compound is :

Question 17 :
In a non stoichiometric sample of ferrous oxide with NaCl structure, the ratio of $Fe^{+3}$ to $Fe^{2+}$ was found to be 0.15. The fraction of octahedral sites occupied by vacancies is :<br/>

Question 18 :
In a cubic arrangement of atoms of A, B and C, atoms of A are present at the corners of the unit cell, B atoms are at face centers and C at tetrahedral voids. If one of the atom from one corner is missing in the unit cell, then the simplest formula of the compound will be:

Question 19 :
A crystal of sodium hydride has an fcc unit cell of $\text{H}^-$ ions with $\text{Na}^+$ ions at the body centres of a unit cell and in the centre of&#160;edges. The number of&#160;$\text{H}^-$&#160;that touch each $\text{Na}^+$ is:

Question 20 :
A crystalline solid between A and B has the following arrangement of atoms:&#160;<br/>(i) Atoms A are arranged in a CCP&#160;array.<br/>(ii) Atoms B occupy all the octahedral voids and half of the tetrahedral voids.<br/>What is the formula of the compound?<br/>