A cubic unit cell of a metal with molar mass of 63.55 ~g ~mol^ -1 has an edge length of 362 pm . Its density is 8.92 ~g ~cm^ -3 . The type of unit cell is

Correct answer: B. face centred aligned & Density =(Z × M)/(a^3 × N_A) & =(d × N_A × a^3)/(M) & = 8.92 × 6.023 × 10^ 23 ×(362 × 10^ -10 )^3 63.55 =4 aligned The metal crystallises in fcc.

JIPMER 2017

Exam: JIPMER
Year: 2017
Subject: Chemistry
Chapter: Solid State

JIPMER 2017 · Chemistry · Solid State

A cubic unit cell of a metal with molar mass of 63.55 ~g ~mol^ -1...

A cubic unit cell of a metal with molar mass of

63.55 \mathrm{~g} \mathrm{~mol}^{-1}

has an edge length of 362 pm . Its density is

8.92 \mathrm{~g} \mathrm{~cm}^{-3}

. The type of unit cell is

Options

Aprimitive
Bface centred
Cend centred
Dbody centred

Correct answer

B. face centred

Step-by-step solution

\begin{aligned}& \text{ Density }=\frac{Z \times M}{a^3 \times N_A} \Z & =\frac{d \times N_A \times a^3}{M} \\ & =\frac{8.92 \times 6.023 \times 10^{23} \times\left(362 \times 10^{-10}\right)^3}{63.55}=4\end{aligned}

\therefore$ The metal crystallises in fcc.

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