How many molecules are present in $0.500$ mole of $N_2{O}_5$? (Use $N_A=6.022\times {10}^{23}$ molecules/mol.)

• A. $3.01\times {10}^{24}$ molecules
• B. $3.01\times {10}^{23}$ molecules
• C. $1.20\times {10}^{23}$ molecules
• D. $6.02\times {10}^{23}$ molecules

Answer: (B)