Question

The element chlorine consists of mixture of 75.53% ${}_{17}$Cl${}^{35}$ and 24.47% ${}_{17}$Cl${}^{37}$ having a mass of 34.97 amu and 36.95 amu, respectively. The atomic weight of chloride is:

• A. 35.25
• B. 35.45
• C. 36.25
• D. 36.45

Answer 1

Answer: (B)

35.45

Given - ${}_{17}C{l}^{35}-75.53$% and mass of $Cl$ 34.97 amu
${}_{17}{C}^{37}-24.47$% and mass of $Cl$ 36.95 amu
$\therefore$ Atomic weight of chlorine
$=\frac{(75.53\times 34.97)+(24.47\times 36.95)}{100}=\frac{3545.45}{100}$
$=35.45$