Ncert Exercises & Solutions

Identify the compounds A, X and Z in the following reactions.

$A + 2 HCl + 5 H_{2} O \to 2 NaCl + X$

$X \to_{370 K}^{∆} {HBO}_{2} \to_{370 K}^{∆} Z$

(i)

\underset{Borox (A)}{{Na}_{2} B_{4} O_{7}} + 2 HCl + 5 H_{2} O \to 2 NaCl + \underset{Orthobodirc acid (X)}{4 H_{3} {BO}_{3}}

(ii) $H_{3} {BO}_{3} \overset{∆ 370 K}{\to} \underset{Metaboric acid}{{HBO}_{2}} + H_{2} O$

(iii) $4 {HBO}_{2} \to_{H_{2} O}^{∆ 370 K} \underset{Tetraboric}{[H_{2} B_{4} O_{7}]}$
$acid \to_{Heat}^{Red} \underset{Boron trioxide (Z)}{3 B_{2} O_{2} + H_{2} O}$