Answer 1

CH₃CH₂OH

2(x) + 6(+1) + 1(-2) = 0 or 2x + 4 = 0

or x = -2

Hence, the O.N. of C is –2.

Answer 2

By conventional method O.N of C  in CH_3CH_2OH = 

or 2x + 6(+1) + 1(-2) = 0 or x = -2