Question

Chlorine has two naturally occurring isotopes,${}^{35}Cl$ and ${}^{37}Cl$. If the atomic mass of $Cl$ is 35.45, the ratio of natural abundance of ${}^{35}Cland{}^{37}Cl$ is closest to

• A. 3.5:1
• B. 3:1
• C. 2.5:1
• D. 4:1

Answer 1

The correct option is B 3:1

$M_{av}=M_1{n}_1+M_2{n}_{2}35.45=35n_1+37(1-n_1)n_1=0.775So,n_2=0.225n_1:n_2=3:1$