How much oxygen is required to burn 1.6 mol of boron?

In accordance with the condition of the problem, we write down the equation, arrange the coefficients:
4B + 3O2 = 2B2O3 – combustion reaction, boron oxide is released;
Let’s make a proportion using these equations:
1.6 mol (B) – X mol (O2);
-4 mol -3 mol from here, X mol (O2) = 1.6 * 3/4 = 1.2 mol.
Answer: to burn boron you need oxygen in the amount of 1.2 mol.