The number of neutrons present in the more abundant isotope of boron is ''. Amorphous boron upon heating with air forms a product, in which the oxidation state of boron is ''. The value of is

Question

The number of neutrons present in the more abundant isotope of boron is ''. Amorphous boron upon heating with air forms a product, in which the oxidation state of boron is ''. The value of  is

Canvas Classes · Accepted Answer

Finding x:
Boron has two isotopes:  (20%) and  (80%).

More abundant isotope =

Neutrons in  = 11 - 5 = 6

So .

Finding y:
Amorphous boron on heating with air (oxygen):

In : oxidation state of B =

So .

Wait — answer key = (2) 9. But option (4) = 6. Let me recheck: , , . ✓

Answer: Option (2) — 9

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