The setting of cement is an ....... process.

$CCP$ lattice of a solid made up of $B^{-}$ ions has an edge length of $3 \ \mathring{A}$ and a density of $5 \ g/cm^3$. If in this lattice $A^{+}$ ions are placed at alternate tetrahedral voids,then the percentage increase in density will be $............. \ \%$. [Molar mass of $A^{+} = 30 \ g/mol$,$N_A = 6 \times 10^{23}$]

Match the following:

List-$I$	List-$II$
$A$. $ABCABC...$ layers	$I$. $F$-centres
$B$. Thermodynamics defects	$II$. $X$-ray diffraction
$C$. $Farbenzenter$	$III$. Vacancy defects
$D$. $Debye-Scherrer$ method	$IV$. Semiconductors
	$V$. Silver

Give the correct order of initials $T$ (true) or $F$ (false) for the following statements:
$I.$ In an anti-fluorite structure,anions form $FCC$ lattice and cations occupy all tetrahedral voids.
$II.$ If the radius of cations and anions are $0.2 \ \mathring{A}$ and $0.95 \ \mathring{A}$,then the coordination number of the cation in the crystal is $4$.
$III.$ An atom/ion is transferred from a lattice site to an interstitial position in a Frenkel defect.
$IV.$ The density of a crystal always increases due to a substitutional impurity defect.

Silver (atomic weight $= 108 \ g \ mol^{-1}$) has a density of $10.5 \ g \ cm^{-3}$. The number of silver atoms on a surface of area $10^{-12} \ m^2$ can be expressed in scientific notation as $y \times 10^x$. The value of $x$ is

Which one of the following statements is correct?