Question

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

(1) 4 

(2) 6 

(3) 3 

(4) 9

Answer 1

Correct option is (4) 9

More abundant isotope \(= B^{11}\)

[Number of neutrons = 6]

x = 6

\(B + O_2 \rightarrow B_2 O_3\)

Oxidation state of B in \(B_2O_3 = +3 \)

So, y = 3 

Hence x + y = 9