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JEE Main levelSingle correct optionDifficulty 2 of 3pb173

An aqueous solution of borax, $Na X_{2} B X_{4} O X_{7}$ , is alkaline because

Ait gives $H X^{+}$ on hydrolysis like all salts
Bit dissociates to release $OH X^{-}$ ions directly from its lattice
Cit hydrolyses to give $NaOH$ (strong base) and the weak acid $B (OH) X_{3}$
D $Na X^{+}$ ions react with water to form $NaOH$ and $H X^{+}$

Answer: C

Borax is the salt of a strong base and a weak acid:

Na X_{2} B X_{4} O X_{7} + 7 H X_{2} O 2 NaOH + 4 B (OH) X_{3}

. The strong base ionises fully while the weak acid hardly ionises, so the solution is alkaline.

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