JEE Main 2022 · 30 Jun · Shift 1 · Chemistry Q61

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ChemistrySingle correct+4 / -1Question 61 of 90

An element X has a body centred cubic (bcc) structure with a cell edge of 200 pm. The density of the element is 5 g cm $^{-3}$ . The number of atoms present in 300 g of the element X is ______.

Given : Avogadro constant, $N_A=6.0\times10^{23}$ mol $^{-1}$ .

N_A

N_A

N_A

N_A

Answer and worked solution

Official answer: D

Molar mass. $M=\dfrac{\rho a^3N_A}Z=\dfrac{5\times8\times10^{-24}\times6\times10^{23}}2=12$ g mol $^{-1}$ .

Atoms $\frac{300}{12}=25$ mol: $25N_A$ .

(D)

Topics:Density of crystals

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JEE Main 2022 · 30 Jun · Shift 1, Chemistry question 61