Question

the number of electrons present in 6.75 gram of aluminium 3 + ion is A)3.01*10^24 B)1.5*10^21 C)6.02*10^22 D)1.5*10^24

Answer 1

Given:

The mass of Al3+ = 6.75 gm

To Find:

The no of electrons in the given mass of Al3+.

Calculation:

- The no of moles in 6.75 gm Al3+ = 6.75/27 = 0.25

- The no of Al3+ ions = 0.25 × 6.022 × 10²³ = 1.5 × 10²³

- One Al atom contains 13 electrons.

⇒ One Al3+ ion contains 10 electrons.

- Total no of electrons in 0.25 moles = 10 × 1.5 × 10²³

⇒ N = 1.5 × 10²⁴

- So, the correct answer is option (D) 1.5 × 10²⁴.