CUET · CHEMISTRY · PYQ PAPER 2023

An element ' \(Y\) ' has a body centred cubic (bec) structure with a cell edge of 144 pm . The density of the element is \(3.6 g / cm ^3\). How many atoms are present in 720 g of the element?

A \(14.24 \times 1023\) atoms
B \(10.42 \times 1025\) atoms
C \(24.16 \times 1023\) atoms
D \(13.42 \times 1025\) atoms

Verified Solution

Answer & Solution

Correct Answer

(D) \(13.42 \times 1025\) atoms

Step-by-step Solution

Detailed explanation

\(V = a^3 = (144 \times 10^{-10} \text{ cm})^3\) \(V = 2.985984 \times 10^{-24} \text{ cm}^3\) \(M = \frac{\rho \times N_A \times V}{Z}\) \(M = \frac{3.6 \text{ g/cm}^3 \times 6.022 \times 10^{23} \text{ mol}^{-1} \times 2.985984 \times 10^{-24} \text{ cm}^3}{2}\)…

Apply the relevant identity from the chapter and substitute the values established in the previous step, keeping the original constraint in view.

Use the simplified expression to isolate the unknown, then plug the result back into the question setup to confirm the working is internally consistent.

Cross-check against a boundary or limiting case. Both the dimensional balance and the qualitative behaviour at the extreme should agree with the candidate answer.

Combine the steps above to identify the correct option. The remaining choices each fail at least one of the consistency, dimensional, or boundary checks.

Same subject

Explore more questions on app

From CUET

Explore more questions on app

List-I (Reaction Name)	List-II (Reaction)

(A) Rosenmund Reaction	(I)
(B) Stephen Reaction	(II)
(C) Gattermann Koch Reaction	(III)
(D) Etard Reaction	(IV)

List-I	List-II
(A) \(A^T=A\)	(I) A is a singular matrix
(B) \(A^T=-A\)	(II) A is a non-singular matrix
(C) \(\|A\|=0\)	(III) A is a skew symmetric matrix
(D) \(\|A\| \neq 0\)	(IV) \(A\) is a symmetric matrix