Question

Calculate number of electrons present in 9.5 g of $P{O}_4^{3-}$:

• A. $6$
• B. $5N_A$
• C. $0.1N_A$
• D. $4.7N_A$

Answer 1

Answer: (B)

$5N_A$

No. of electrons present in O=8 and P=15

Electron present in 1 molecule $=15+4\times 8+3=50$

Electron present in 1 mole $=50N_A$

Total mole $=\frac{9.5}{(31+16\times 4)}=\frac{9.5}{95}$

Total no. of electrons in $P{O}_4^{3-}=50\times \frac{9.5}{95}{N}_A=5N_A$

Hence, the correct option is B.