p-Block Elements-I - Result Question 26
26.
(i) How is boron obtained from borax? Give chemical equations with reaction conditions.
(ii) Write the structure of $B _2 H _6$ and its reaction with $HCl$.
(2002)
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Solution:
- (i) $Na _2 B _4 O _7+HCl \longrightarrow NaCl+H _3 BO _3$
$ \begin{gathered} H_3BO_3+HCl \stackrel{\Delta}{\longrightarrow} BCl_3+H_2O \` BCl3+Al \stackrel{\Delta}{\longrightarrow} B+AlCl3 \end{gathered} $
(ii) $B _2 H _6$ :
It has $4$ terminal $B-H$ bonds. There are two $B-H-B$, three two-electron centred bridged bonds.
$B_2H_6+HCl \longrightarrow B_2H_5Cl+H_2$
BETA
