Question

Assertion :$16$ g each of $O_2$ and $O_3$ contains $\frac{N_A}{2}$ and $\frac{N_A}{3}$ atoms respectively. Reason: $16$ g each of $O_2$ and $O_3$ contains same number of atoms.

• A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
• B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
• C. Assertion is correct but Reason is incorrect
• D. Assertion is incorrect but Reason is correct

Answer 1

The correct option is D Assertion is incorrect but Reason is correct

The molar mass of $O_2$ and $O_3$ are 32 g/mol and 48 g/mol respectively.

$16$ g each of $O_2$ and $O_3$ corresponds to $\frac{16}{32}=\frac{1}{2}$ moles and $\frac{16}{48}=\frac{1}{3}$ moles respectively.

$16$ g each of $O_2$ and $O_3$ contains $\frac{N_A}{2}$ and $\frac{N_A}{3}$ molecules (not atoms) respectively.

$16$ g of $O_2$ contains-

$\Rightarrow \frac{16}{32}\times N_A\times 2=N_{A}atoms$

$16$ g of $O_3$ contains-

$\Rightarrow \frac{16}{48}\times N_A\times 3=N_{A}atoms$

16 g of each $O_2$ and $O_3$ contains same no. of atoms, i.e $N_{A}atoms$

Hence, Assertion is incorrect but Reason is correct