JEE Main 2002 — Some Basic Concepts Of Chemistry Question with Solution

Number of moles of Fe in 558.5 gm of Fe is

$$=$$ $$\frac{558.5}{55.85}$$

$$=$$ 10

$$\therefore$$ Number moles of Fe in 558.5 gm Fe is = 10

Since here Fe is monoatomic then no. of atoms in 10 moles Fe is

$$\Rightarrow$$ 10 $$\times$$ 1 $$\times$$ N_A

$$\Rightarrow$$ 10 N_A

For Option (A) Atomic Mass of Carbon is 12 g then no. of moles in 60 g Carbon is

$$\Rightarrow$$ $$\frac{60}{12}=5$$

Here Carbon is also monoatomic then no. of atoms in 5 moles of Carbon

$$\Rightarrow$$ 5 $$\times$$ 1 $$\times$$ N_A

$$\Rightarrow$$ 5 N_A

Now we can clearly see 10 is twice of 5, so option (A) is correct.