Leaching Bauxite Ore with NaOH
The process described is the initial step of the Bayer process used for extracting alumina from bauxite ore.
Bauxite ore, containing aluminum oxide ($Al_2O_3$), is treated with a hot, concentrated sodium hydroxide ($NaOH$) solution. Aluminum oxide is amphoteric and reacts with the strong alkali:
$Al_2O_3(s) + 2NaOH(aq) + 3H_2O(l) \rightarrow 2Na[Al(OH)_4](aq)$
This reaction dissolves the aluminum oxide, forming soluble sodium tetrahydroxoaluminate. This solution is represented as 'X'.
Precipitation using Carbon Dioxide
To recover pure aluminum hydroxide, carbon dioxide ($CO_2$) gas is bubbled through the alkaline solution containing 'X'. $CO_2$ acts as an acidic gas and neutralizes the alkali, causing the precipitation of aluminum hydroxide.
The reaction is:
$2Na[Al(OH)_4](aq) + CO_2(g) \rightarrow 2Al(OH)_3(s) + Na_2CO_3(aq) + H_2O(l)$
The precipitated solid, 'Y', is aluminum hydroxide, which is a hydrated compound. It is often represented in its hydrated oxide form, $Al_2O_3.xH_2O$, after drying and heating.
Identifying X and Y
Based on the reactions:
- 'X' is the sodium salt formed after digesting bauxite with NaOH, which is $Na[Al(OH)_4]$.
- 'Y' is the hydrated compound precipitated when $CO_2$ is passed through the solution of 'X', which is $Al(OH)_3$, represented as $Al_2O_3.xH_2O$.
Therefore, the correct option identifies 'X' as $Na[Al(OH)_4]$ and 'Y' as $Al_2O_3.xH_2O$.
Similar Questions
- A chromium complex with a formula $\text{CrCl}_3\cdot 6\text{H}_2\text{O}$ has a spin only magnetic moment value of $3.87 \text{ BM}$ and its solution conductivity corresponds to $1 : 2$ electrolyte. $2.75 \text{ g}$ of the complex solution was initially passed through a cation exchanger. The solution obtained after the process was reacted with excess of $\text{AgNO}_3$. The amount of $\text{AgCl}$ formed in the above process is _____ g. (Nearest integer)
[Given: Molar mass in $\text{g mol}^{-1}$ $\text{Cr} : 52; \text{Cl}: 35.5, \text{Ag}: 108, \text{O}: 16, \text{H}: 1$] - Consider the following reactions :
$\text{NaCl} + \text{K}_2\text{Cr}_2\text{O}_7 + \text{H}_2\text{SO}_4 \rightarrow \text{A} + \text{KHSO}_4 + \text{NaHSO}_4 + \text{H}_2\text{O}$
$\text{A} + \text{NaOH} \rightarrow \text{B} + \text{NaCl} + \text{H}_2\text{O}$
$\text{B} + \text{H}_2\text{SO}_4 + \text{H}_2\text{O}_2 \rightarrow \text{C} + \text{Na}_2\text{SO}_4 + \text{H}_2\text{O}$
In the product 'C', 'X' is the number of $\text{O}_2^{2-}$ units, 'Y' is the total number oxygen atoms present and 'Z' is the oxidation state of Cr. The value of X + Y + Z is ____________. - Identify the metal ions among $\text{Co}^{2+}, \text{Ni}^{2+}, \text{Fe}^{2+}, \text{V}^{3+}$ and $\text{Ti}^{2+}$ having a spin-only magnetic moment value more than $3.0\text{ BM}$. The sum of unpaired electrons present in the high spin octahedral complexes formed by those metal ions is __________.
The crystal field splitting energy of $[\text{Co(oxalate)}_3]^{3-}$ complex is '$n$' times that of the $[\text{Cr(oxalate)}_3]^{3-}$ complex. Here '$n$' is ___________. (Assume $\Delta_o >> P$)
- A metal complex with a formula $MCl_4.3NH_3$ is involved in $sp^3d^2$ hybridisation. It upon reaction with excess of $AgNO_3$ solution gives 'x' moles of AgCl. Consider 'x' is equal to the number of lone pairs of electron present in central atom of $BrF_5$. Then the number of geometrical isomers exhibited by the complex is ______
- Consider the molecules / ions given below
$XeO_3$, $BF_4^-$, $I_3^-$, $SF_6$, $PCl_5$
The ratio of number of molecules having $sp^3d$ hybridisation to those having $sp^3$ hybridisation is ________ - The total number of possible isomers for square- planar $[Pt(Cl)(NO_2)(NO_3)(SCN)]^{2–}$ is :-
- In $KO_2$, the nature of oxygen species and the oxidation state of oxygen atom are, respectively
The correct order of spin-only magnetic moments among the following is :
(Atomic number : Mn = 25, Co = 27, Ni= 28, Zn = 30)
- Biochemical Oxygen Demand (BOD) value can be a measure of water pollution caused by the organic matter. Which of the following statements is correct -
Important Questions from Inorganic Chemistry
- A chromium complex with a formula $\text{CrCl}_3\cdot 6\text{H}_2\text{O}$ has a spin only magnetic moment value of $3.87 \text{ BM}$ and its solution conductivity corresponds to $1 : 2$ electrolyte. $2.75 \text{ g}$ of the complex solution was initially passed through a cation exchanger. The solution obtained after the process was reacted with excess of $\text{AgNO}_3$. The amount of $\text{AgCl}$ formed in the above process is _____ g. (Nearest integer)
[Given: Molar mass in $\text{g mol}^{-1}$ $\text{Cr} : 52; \text{Cl}: 35.5, \text{Ag}: 108, \text{O}: 16, \text{H}: 1$] - Consider the following reactions :
$\text{NaCl} + \text{K}_2\text{Cr}_2\text{O}_7 + \text{H}_2\text{SO}_4 \rightarrow \text{A} + \text{KHSO}_4 + \text{NaHSO}_4 + \text{H}_2\text{O}$
$\text{A} + \text{NaOH} \rightarrow \text{B} + \text{NaCl} + \text{H}_2\text{O}$
$\text{B} + \text{H}_2\text{SO}_4 + \text{H}_2\text{O}_2 \rightarrow \text{C} + \text{Na}_2\text{SO}_4 + \text{H}_2\text{O}$
In the product 'C', 'X' is the number of $\text{O}_2^{2-}$ units, 'Y' is the total number oxygen atoms present and 'Z' is the oxidation state of Cr. The value of X + Y + Z is ____________. - Identify the metal ions among $\text{Co}^{2+}, \text{Ni}^{2+}, \text{Fe}^{2+}, \text{V}^{3+}$ and $\text{Ti}^{2+}$ having a spin-only magnetic moment value more than $3.0\text{ BM}$. The sum of unpaired electrons present in the high spin octahedral complexes formed by those metal ions is __________.
The crystal field splitting energy of $[\text{Co(oxalate)}_3]^{3-}$ complex is '$n$' times that of the $[\text{Cr(oxalate)}_3]^{3-}$ complex. Here '$n$' is ___________. (Assume $\Delta_o >> P$)
- Which of the following is the structure of pyrosulphuric acid?
