The relative atomic mass of Boron in trimethyl borate [(CH3O)3B] is; 10.8
According to the question;
The relative abundance of Boron in the spectrum is;
Relative atomic mass = (80% of 11) + (20% of 10)
Hence, the relative atomic mass of Boron in trimethyl borate [(CH3O)3B] is; 10.8
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