If ‘a’ is the length of the side of the cube, the distance between the body centered atom and one corner atom in the cube will be_________.

(a)

\(\left( \cfrac { 2 }{ \sqrt { 3 } } \right) a\)

(b)

\(\left( \cfrac { 4 }{ \sqrt { 3 } } \right) a\)

(c)

\(\left( \cfrac { \sqrt { 3 } }{ 4 } \right) a\)

(d)

\(\left( \cfrac { \sqrt { 3 } }{ 2 } \right) a\)

Potassium has a bcc structure with nearest neighbor distance 4.52 \(\overset{o}{A}\). Its atomic weight is 39. its density will be_______.

(a)

915 kg m^-3

(b)

2142 kg m^-3

(c)

452 kg m^-3

(d)

390 kg m^-3

Schottky defect in a crystal is observed when ______.

(a)

unequal number of anions and anions are missing from the lattice

(b)

Equal number of cations and anions are missing from the lattice

(c)

an ion leaves its normal site and occupies an interstitial site

(d)

no ion is missing from its lattice

Assertion: due to Frenkel defect, density of the crystalline solid decreases.
Reason: In Frenkel defect cation and anion leaves the crystal.
Codes:
a) Both assertion and reason are true and reason is the correct explanation of assertion
b) Both assertion and reason are true but reason is not the correct explanation of assertion
c) Assertion is true but reason is false
d) Both assertion and reason are false

(a)

Both assertion and reason are true and reason is the correct explanation of assertion

(b)

Both assertion and reason are true but reason is not the correct explanation of assertion

(c)

Assertion is true but reason is false

(d)

Both assertion and reason are false

A two dimensional solid pattern formed by two different atoms X and Y is shown below. The black and white squares represent atoms X and Y respectively. The simplest formula for the compound based on the unit cell from the pattern is _______.

(a)

XY₈

(b)

X₄Y₉

(c)

XY₂

(d)

XY₄