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Atomic weight of Boron is 10.81 and it has two isotopes 5B10 and 5B11 .Then the ratio 5B10 : 5B11 in nature would be
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- 19 : 81
- 10 : 11
- 15 : 16
- 81 : 19
Correct Option: A
Suppose that, The number of 10 B type atoms = x
and the number of 11 B type atoms = y
Weight of 10 B type atoms = 10x
Weight of 11 B type atoms = 11y
Total number of atoms = x + y
∴ Atomic weight
| = | = 10.81 | x + y |
⇒ 10x + 11y = 10.81x + 10.81 y
⇒ 0.81x = 0.19 y
| ⇒ | = | |||
| y | 81 |
