Atoms And Nuclei Question 332

Question: Atomic weight of boron is 10.81 and it has two isotopes $ _{5}B^{10} $ and $ _{5}B^{11} $ . Then ratio of $ _{5}B^{10}: _{5}B^{11} $ in nature would be

Options:

A) 19 : 81

B) 10 : 11

C) 15 : 16

D) 81 : 19

Show Answer

Answer:

Correct Answer: A

Solution:

  • Let the percentage of $ B^{10} $ atoms be x, then average atomic weight $ =\frac{10x+11(100-x)}{100}=10.81\Rightarrow x=19 $
    $ \therefore ,\frac{{N_{B^{10}}}}{{N_{B^{11}}}}=\frac{19}{81} $


NCERT Chapter Video Solution

Dual Pane