Question

Find the number of oxygen atoms in 10 millimnoles of $\left[Fe\right(H_{2}O{)}_{5}NO]S{O}_4$.

• A. $0.01N_A$
• B. $0.1N_A$
• C. $N_A$
• D. $10N_A$

Answer 1

The correct option is B $0.1N_A$

Number of O-atoms in one formula unit of $\left[Fe\right(H_{2}O{)}_{5}NO]S{O}_4=10$

Therefore, number of O-atoms in one mole of $\left[Fe\right(H_{2}O{)}_{5}NO]S{O}_4=10N_A$

So, number of O-atoms in 10 millimoles of $\left[Fe\right(H_{2}O{)}_{5}NO]S{O}_4$
$=10\times {10}^{-3}\times 10N_A$
$=0.1N_A$