Question

1)Al->Na[Al(OH)4]->AlCl3->Al(OH)3->Al2O3->Al 2)Cr2(SO4)3->Cr(OH)3->Cr2O3->Cr->CrCl2->CrCl3->Na[Cr(OH)6]

Answer 1

1)Al(OH)3 + NaOH → Na[Al(OH)4]
Na[Al(OH)4] + 4HCl → AlCl3 + NaCl + 4H2O
AlCl3 + 3NaOH → Al(OH)3 + 3NaCl
2Al(OH)3  t→ Al2O3 + 3H2O
2Al2O3 →  4Al + 3O2
2) Cr2(SO4)3 + 6NaOH → 2Cr(OH)3 + 3Na2SO4
2Cr(OH)3    t→ Cr2O3 + 3H2O
Cr2O3 + 2Al   t→ 2Cr + Al2O3
Cr + 2HCl  t→2 CrCl2 + H2
4CrCl2 + O2 + 4HCl → 4CrCl3 + 2H2O
CrCl3 + 6NaOH → Na3[Cr(OH)6] + 3NaCl

Answer 2

It seems like you've provided two sequences of chemical reactions. Let's go through each of them:

1. Al -> Na[Al(OH)4] -> AlCl3 -> Al(OH)3 -> Al2O3 -> Al

This sequence shows the transformation of aluminum (Al) through several reactions. Here's a breakdown of each step:

• Al reacts with NaOH to form Na[Al(OH)4], which is a complex ion formed when aluminum hydroxide reacts with sodium hydroxide.
• Na[Al(OH)4] can then be further reacted with HCl to yield AlCl3, which is aluminum chloride.
• AlCl3 can react with water (H2O) to produce Al(OH)3, which is aluminum hydroxide.
• Al(OH)3 can undergo dehydration to form Al2O3, which is aluminum oxide.
• Finally, Al2O3 represents aluminum oxide, which can be reduced to elemental aluminum (Al) through a suitable reduction process.

2. Cr2(SO4)3 -> Cr(OH)3 -> Cr2O3 -> Cr -> CrCl2 -> CrCl3 -> Na[Cr(OH)6]

This sequence illustrates the transformation of chromium (Cr) through a series of reactions. Here's a breakdown of each step:

• Cr2(SO4)3 represents chromium sulfate, which can react with a base like NaOH to yield Cr(OH)3, which is chromium hydroxide.
• Cr(OH)3 can undergo thermal decomposition to form Cr2O3, which is chromium(III) oxide.
• Cr2O3 can be further reduced to elemental chromium (Cr).
• Cr can react with HCl to form CrCl2, which is chromium(II) chloride.
• CrCl2 can be oxidized with an appropriate oxidizing agent to yield CrCl3, which is chromium(III) chloride.
• Na[Cr(OH)6] represents the complex ion formed when sodium hydroxide reacts with chromium(III) chloride.

Please note that these sequences are simplified representations, and in practical scenarios, the reactions might involve specific conditions, catalysts, and other reactants.