0.553 g of a boron - hydrogen compound created a pressure of 0.658 atm in a bulb of 407 mL at $100^{\large\circ}C$. Analysis showed it to $85.7\%$ boron . Calculate its molecular formula.

Question

$(a)\;B_4H_6\qquad(b)\;B_3H_8\qquad(c)\;B_5H_7\qquad(d)\;B_5H_9$