3 moles of ${\mathrm{B}}_2{\mathrm{H}}_6$ are completely reacted with methanol. The number of moles of Boron containing  product formed is __?

One mole of diborane with methanol gives 2 moles of boron containing product

${\mathrm{B}}_2{\mathrm{H}}_6+6{\mathrm{CH}}_3\mathrm{OH}\to 2 \mathrm{B}{\left({\mathrm{OCH}}_3\right)}_3+6{\mathrm{H}}_2$

$\text{ For }3\text{ moles of }{\mathrm{B}}_2{\mathrm{H}}_6,\text{ product formed }=6\text{ moles }$