a. the mass spectra with labelled axes is attached
b. relative atomic mass of boron is 10.8 u.
The mass spectrum of boron shows two peaks, one at m/z 10 and the other at m/z 11. The intensity of the peak at m/z 10 is 19.8%, while the intensity of the peak at m/z 11 is 80.2%. This is because boron has two naturally occurring isotopes, 10B and 11B. The relative abundance of these isotopes is reflected in the intensities of the peaks in the mass spectrum.
Relative atomic mass = (mass of isotope 1 * abundance of isotope 1) + (mass of isotope 2 * abundance of isotope 2)
e mass of 10B = 10.0129 u
the mass of 11B = 11.0093 u.
The abundance of 10B = 19.8%, and the abundance of 11B = 80.2%.
Relative atomic mass = (10.0129 u * 0.198) + (11.0093 u * 0.802)
= 10.8 u
In conclusion, the relative atomic mass of boron is 10.8 u.