Get Answers to all your Questions

header-bg qa

11.28: When metal X is treated with sodium hydroxide, a white precipitate (A) is obtained, which is soluble in excess of NaOH to give soluble complex (B). Compound (A) is soluble in dilute HCl to form compound (C). The compound (A), when heated strongly, gives (D), which is used to extract metal. Identify (X), (A), (B), (C) and (D). Write suitable equations to support their identities.

Answers (1)

best_answer

In given information, when X is treated with sodium hydroxide, it gives A (white ppt) and it is soluble in excess of NaOH. Thus X must be aluminium. So, the white ppt of A is aluminium hydroxide. 
The complex B is soluble in excess of sodium hydroxide So it means it is a sodium tetrahydroxy aluminate(II) complex.

\\2Al+3NaOH\rightarrow Al(OH)_3+3Na^+\\ Al(OH)_{3}+NaOH\rightarrow Na[Al(OH)_{3}]^-

Now, when we add dilute HCl to aluminium hydroxide, it gives the compound C (aluminium chloride).

Al(OH)_{3}+3HCl\rightarrow AlCl_{3}+3H_{2}O
   (A)                                           (C)

And when compound (A) is heated strongly, it gives D and this compound used to extract metal X

2Al(OH)_{3}\rightarrow Al_2O_{3}+3H_{2}O
     (A)                          (D)

Posted by

manish

View full answer

Crack CUET with india's "Best Teachers"

  • HD Video Lectures
  • Unlimited Mock Tests
  • Faculty Support
cuet_ads