Chemistry - Solid State Question with Solution | TestHub

ChemistrySolid StateCubic CrystalsMedium2 minQB

ChemistryMediumsingle choice

Passage / Comprehension

Cadmium oxide crystallizes in an NaCl-type structure. The compound is, however, non-stoichiometric with the formula CdO₀.₉₅. The defect arises due to some cationic positions being occupied by neutral Cd atoms in place of Cd²⁺ ions, and an equivalent number of anion sites are vacant. (Cd = 112, $N_{A} = 6 \times 1 0^{23}$ )

If the edge length of the unit cell is 400 pm , what would be the density ( $in gm / cm^{3}$ ) of perfect solid?

Options:

Answer:

Solution:

$a = 400 p m = 4 \times 1 0^{- 8} c m$ , $Z = 4$ (NaCl type), $M_{C d O} = 112 + 16 = 128 g / m o l$

$ρ = \frac{ZM}{N _{A} a ^{3}} = \frac{4 \times 128}{6.022 \times 1 0 ^{23} \times ( 4 \times 1 0 ^{- 8} ) ^{3}}$

$a^{3} = 64 \times 1 0^{- 24} = 6.4 \times 1 0^{- 23} c m^{3}$

$ρ \approx \frac{512}{6.022 \times 1 0 ^{23} \times 6.4 \times 1 0 ^{- 23}} \approx 13.33 g / c m^{3}$

Stream:JEESubject:ChemistryTopic:Solid StateSubtopic:Cubic Crystals

⏱ 2mℹ️ Source: QB

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