Question

Crystalline boron in small amounts may be obtained by :

• A. Reducing BCl3 with H2
• B. Pyrolysis of BiI3
• C. Thermal decomposition of diborane
• D. All of these

Answer 1

Answer: (D)

All of these

Answer 2

(1) 2BX3 + 3H2 $\underset{orTantalum}{\overset{\quad redhotW\quad}{\rightarrow}}$ 2B + 6HX

(X = Cl or Br)

(2) 2Bl3 $\underset{orTantalum}{\overset{\quad redhotW\quad}{\rightarrow}}$ 2B + 3I2.

(Van Arkel mehod).

(3) B2H6$\overset{\quad\Delta\quad}{\rightarrow}$ 2B + 3H2.