Question

44. If the density of crystalline CsCl is 3.988 g/cm3,
calculate the volume effectively occupied by a
single CsClion pair in the crystal. (CsCl =168.4)
(1) 7.01 * 10-23 cm
(2) 6.02 x 10-24 cm
(3) 1 cm3
(4) 3.5 x 10-23 cm3​

Answer 1

• The volume effectively occupied by a single CsCl ion pair in the crystal is 7.01 × 10⁻²³ cm³.

Given-

Density of crystalline CsCl is = 3.988 g/cm³

Molecular weight of CsCl is = 168.4 g/mol

CsCl forms BCC structure. So, density of crystalline CsCl can be given by-

ρ = M Z/NA ×a³ where M is the molecular mass, Z is the Number of atoms present in BCC, NA is Avagadro number

ρ = 3.968 g/cm³

a³ = 168.4 × 2/ 6.023 × 10²³ × 3.988

a³ = 14.023 × 10⁻²³ cm³

So, for single ion = 14.023 × 10⁻²³ cm³ /2

a³ = 7.01 × 10⁻²³ cm³

Hope this helps you

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