In order to obtain one tonne of aluminum, the following inputs are required: four tonnes of bauxite, $150 K g$ of sodium hydroxide, and $600 K g$ of graphite. The aluminum compound in bauxite is aluminum oxide and the main impurity is iron $(I I I)$ oxide. Aluminum is obtained by the electrolysis of aluminum oxide dissolved in cryolite.
Write down the word which correctly completes the following sentence: "By dissolving Aluminum oxide in cryolites" (conducting/non-conducting) solution is produced.

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Solution

Alumina or Aluminium oxide( $A l_{2} O_{3}$ ) is highly stable and has a higher melting point
So to reduce the melting point and increase the electrical conductivity of alumina, Cryolite and fluorspar are added to alumina.
Fused electrolyte contains Alumina. Cryolite and a little Fluorspar that is $A l_{2} O_{3} + N a_{3} A l F_{6} + C a F_{2}$ respectively.
The Cryolite added will lower the melting point and also increases the conductivity.
Hence, by dissolving Aluminum oxide in cryolites conducting solution is produced.

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Similar questions

In order to obtain 1 tonner of aluminium, the following inputs are required. 4 tonnes of bauxite, 150 kg of sodium hydroxide and 600 kg of graphite. The aluminium compound in bauxite is aluminium oxide and the main impurity is Iron (III) oxide. Aluminium is obtained by the electrolysis of aluminium oxide dissolved in cryolite.

(a) When bauxite is treated with sodium hydroxide solution, what happens to:

(i) the aluminium oxide,

(ii) the iron (III) oxide?

(b) (i) Name the process used for the purification of bauxite.

(ii) Write the equation for the action of heat on aluminium hydroxide.

(ii) Write down the word which correctly completes the following sentence.By dissolving aluminium oxide in cryolite a ..........(conducting/non conducting) solution is produced.

(iii) Why is so much graphite required for the electrolytic process?

(iv) Write the equation for the reaction which takes palace at cathode.

Q. In order to obtain one tonne of aluminium, the following inputs are required:
4 tonnes of bauxite, 150 kg of sodium hydroxide and 600 kg of graphite.
The aluminium compound in bauxite is aluminium oxide and the main impurity is iron (III) oxide. Aluminium is obtained by the electrolysis of aluminium oxide dissolved in cryolite.
(a) When bauxite is treated with sodium hydroxide solution, what happens to:
(i) the aluminium oxide?
(ii) the iron (III) oxide?
(b) (i) Name the process used for the purification of bauxite.
(ii) Write the equation to show the action of heat on aluminium hydroxide.
(c) (i) Write the formula of cryolite.
(ii) Write down the word which correctly completes the following sentence:
"By dissolving aluminium oxide in cryolite, a __________ (conducting/non-conducting) solution is produced.
(iii) Why is so much graphite required for this electrolytic process?
(iv) Write the equation for the reaction which takes place at the cathode.
(d) In construction work, why is the alloy of aluminium, duralumin used rather than pure aluminium.

In order to obtain $1$ tonne of aluminum, the following inputs are required: four tonnes of bauxite, $150 K g$ of sodium hydroxide, and $600 K g$ of graphite. The aluminum compound in bauxite is aluminum oxide and the main impurity is iron $(I I I)$ oxide. Aluminum is obtained by the electrolysis of aluminum oxide dissolved in cryolite.

Write the equation of action of heat on Aluminum Hydroxide

When bauxite is treated with sodium hydroxide solution what happens to:

aluminum oxide?

In order to obtain one tonne of aluminum, the following inputs are required: four tonnes of bauxite, $150 K g$ of Sodium hydroxide, and $600 K g$ of graphite. The aluminum compound in bauxite is aluminum oxide and the main impurity is iron $(I I I)$ oxide. Aluminum is obtained by the electrolysis of aluminum oxide dissolved in cryolite.

Why is so much graphite required for this electrolytic process?

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