Chapter 10, Problem 122RQ

Boron forms a variety of unusual compounds with hydrogen. A chemist isolated 6.3 mg of one of the boron hydrides in a glass bulb with a volume of 385 mL at $\text{25}\text{.0 °C}$ and a bulb pressure of 11 torr. Which of the following is likely to be its molecular formula: ${\text{BH}}_{\text{3}}{\text{, B}}_{\text{2}}{\text{H}}_{\text{6}}{\text{, or B}}_{\text{4}}{\text{H}}_{\text{l0}}$ ?