<p>What volume of&nbsp;<math xmlns="http://www.w3.org/1998/Math/MathML"><msub><mi>H</mi><mn>2</mn></msub></math>&nbsp;at 273 K and 1 atm will be consumed in obtaining 21.6g of elemental boron (at. mass 10.8) from the reduction of boron trichloride with&nbsp;<math xmlns="http://www.w3.org/1998/Math/MathML"><msub><mi>H</mi><mn>2</mn></msub></math>?</p>