$A$ mixture of $KCl$ and $KF$ is added to sodium chloride.

Which of the following is the correct cooling curve for an amorphous solid?

In the given cooling curve,what is the crystallization temperature in $K$?

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.

Among the following,the incorrect statement is:

What is the percent by mass of titanium in rutile,a mineral that contains titanium and oxygen,if the structure can be described as a closest-packed array of oxide ions,with titanium in one half of the octahedral holes? What is the oxidation number of titanium? $(Ti = 48, O = 16)$