What is not true about borax? - Infinity Learn by Sri Chaitanya

A
Molecular formula is ${Na}_{2} B_{4} O_{7} \cdot 10 H_{2} O$ .
B
Crystallic borax contains tetranuclear unit of ${[B_{4} O_{5} (OH)_{4}]}^{2 -}$
C
It hydrolyses to give an acidic solution.
D
White crystalline solid.

Solution:

Formula of borax is ${Na}_{2} B_{4} O_{7} . 10 H_{2} O or {Na}_{2} [B_{4} O_{5} {(OH)}_{4}] . 8 H_{2} O .$ It is a white crystalline solid. On hydrolysis, borax gives a strong base and a weak acid.

${Na}_{2} B_{4} O_{7} + 7 H_{2} O ⟶ \underset{Strong base}{2 NaOH} + \underset{Weak acid}{4 B (OH)_{3}}$

This indicates that after hydrolysis, boric makes a solution alkaline.

Crystalline borax has a tetranuclear unit, ${[B_{4} O_{5} {(OH)}_{4}]}^{2 -} .$

Solution:

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