Most of the ores available in nature contain large amount of impurities i.e. gangue. The pretreatment of ores, based on physical properties and without bringing out any major chemical change in the ore is called ore dressing or ore concentration.Q.In the purification of bauxite by leaching, the chemicals employed in Baeyers and Halls process respectively area)Na2CO3 and NaOHb)NaOH andNa2CO3c)NaOH and C + N2d)Na2CO3 and NaCNCorrect answer is option 'B'. Can you explain this answer?

EduRev

All Courses

Explore Courses UPSC Exam UPSC Test Series Free Notes EduRev Infinity

Open App

Class 12 Exam > Class 12 Questions > Most of the ores available in nature contain ...

Join the Discussion on the App

In the purification of bauxite by leaching, the chemicals employed in Baeyer’s and Hall’s process respectively are

a)
Na₂CO₃and NaOH
b)
NaOH and Na₂CO₃
c)
NaOH and C + N₂
d)
Na₂CO₃and NaCN

Correct answer is option 'B'. Can you explain this answer?

FREE This question is part of

Test: Metallurgy Process of Concentration of Ores (Old NCERT)

Attempt Test

Attempt this Test

Verified Answer

Most of the ores available in nature contain large amount of impuritie...

In the Baeyer process Al₂O₃ is obtained from bauxite ore by treating the powered ore with a strong solution of NaOH when alumina (Al₂O₃) dissolves forming sodium mefa-aluminate leaving behind impurities.

View all questions of this test

Most Upvoted Answer

Most of the ores available in nature contain large amount of impuritie...

Purification of Bauxite by Leaching

Introduction:
Bauxite is a naturally occurring ore that is rich in aluminum oxide. However, it also contains various impurities such as silica, iron oxide, and titanium dioxide. The purification of bauxite involves the removal of these impurities to obtain a pure form of aluminum oxide, also known as alumina.

Bayer's Process:
The Bayer's process is commonly used for the purification of bauxite. In this process, bauxite ore is first crushed and then mixed with a solution of sodium hydroxide (NaOH) at high temperatures and pressures. The mixture is then subjected to leaching, where the impurities are dissolved, leaving behind pure alumina.

Hall's Process:
The Hall's process is another method used for the purification of bauxite. In this process, bauxite ore is first crushed and then mixed with a solution of sodium carbonate (Na2CO3) at high temperatures. The mixture is then subjected to leaching, where the impurities are dissolved, leaving behind pure alumina.

Chemicals Employed:
In the purification of bauxite by leaching, the chemicals employed in Bayer's and Hall's processes respectively are:

- Bayer's Process: Sodium hydroxide (NaOH) is used as the leaching agent in Bayer's process. It reacts with impurities such as silica, iron oxide, and titanium dioxide to form soluble sodium silicate, sodium ferrite, and sodium titanate complexes.

- Hall's Process: Sodium carbonate (Na2CO3) is used as the leaching agent in Hall's process. It reacts with impurities such as silica, iron oxide, and titanium dioxide to form soluble sodium silicate, sodium carbonate, and sodium titanate complexes.

Correct Answer:
Based on the given options, the correct answer is option 'B' - NaOH and Na2CO3. In the purification of bauxite by leaching, NaOH is employed in Bayer's process, while Na2CO3 is employed in Hall's process.

View all answers Start learning for free

< Previous Question Next Question >

Explore Courses for Class 12 exam

Similar Class 12 Doubts

Comprehension TypeThis section contains a passage describing theory, experiments, data, etc. Two questions related to the paragraph have been given. Each question has only one correct answer out of the given 4 options (

View answer

Impure metals are purified by different methods in order to remove the undesired impurities. These methods depend on the nature of metal and nature of impurities. Liquation is used for purifying metals with low melting points like Bi, Sn, Pb, Hg etc. Distillation is used for volatile metals like Zn, Cd, Hg. Cupellation is used to purify silver metal with lead impurities. Electrolytic refining (Cu, Ag, Mg, Al) Zone refining (Si, Ge, G

View answer

Read the passage given below and answer the following questions:The rate of a reaction, which may also be called its velocity or speed, can be defined with relation to the concentration of any of the reacting substances, or to that of any product of the reaction. If the species chosen is a reactant which has a concentration c at time t the rate is - dc/dt, while the rate with reference to a product having a concentration x at time t is dx/dt. Any concentration units may be used for expressing the rate; thus, if moles per liter are employed for concentration and seconds for the time, the units for the rate are moles litre–1sec–1. For gas reactions pressure units are sometimes used in place of concentrations, so that legitimate units for the rate would be (mm. Hg) sec–1 and atm. sec–1 The order of a reaction concerns the dependence of the rate upon the concentrations of reacting substances; thus, if the rate is found experimentally to be proportional to the ath power of the concentration of one of the reactants A, to the both power of the concentration of a second reactant B, and so forth, via., rate = k CAα CAβ the over-all order of the reaction is simply n = α + β + ----- (2) Such a reaction is said to be of the αth order with respect to the substance A, the βth order with respect to B.In the following questions, a statement of Assertion followed by a statement of Reason is given. Choose the correct answer out of the following choices on the basis of the above passage.Assertion: For a reaction: P + 2Q → Products, Rate = k [P]1/2[Q]1 so the order of reaction is 1.5Reason: Order of reaction is the sum of stoichiometric coefficients of the reactants.

View answer

Direction: Read the passage given below and answer the following questions:Boiling point or freezing point of liquid solution would be affected by the dissolved solids in the liquid phase. A soluble solid in solution has the effect of raising its boiling point and depressing its freezing point. The addition of non-volatile substances to a solvent decreases the vapour pressure and the added solute particles affect the formation of pure solvent crystals.According to many researches the decrease in freezing point directly correlated to the concentration of solutes dissolved in the solvent. This phenomenon is expressed as freezing point depression and it is useful for several applications such as freeze concentration of liquid food and to find the molar mass of an unknown solute in the solution. Freeze concentration is a high quality liquid food concentration method where water is removed by forming ice crystals. This is done by cooling the liquid food below the freezing point of the solution. The freezing point depression is referred as a colligative property and it is proportional to the molar concentration of the solution (m), along with vapour pressure lowering, boiling point elevation, and osmotic pressure. These are physical characteristics of solutions that depend only on the identity of the solvent and the concentration of the solute. The characters are not depending on the solute’s identity.Q.Colligative properties are

View answer

Read the passage given below and answer the following questions:The rate of a reaction, which may also be called its velocity or speed, can be defined with relation to the concentration of any of the reacting substances, or to that of any product of the reaction. If the species chosen is a reactant which has a concentration c at time t the rate is - dc/dt, while the rate with reference to a product having a concentration x at time t is dx/dt. Any concentration units may be used for expressing the rate; thus, if moles per liter are employed for concentration and seconds for the time, the units for the rate are moles litre–1sec–1. For gas reactions pressure units are sometimes used in place of concentrations, so that legitimate units for the rate would be (mm. Hg) sec–1 and atm. sec–1 The order of a reaction concerns the dependence of the rate upon the concentrations of reacting substances; thus, if the rate is found experimentally to be proportional to the ath power of the concentration of one of the reactants A, to the both power of the concentration of a second reactant B, and so forth, via., rate = k CAα CAβ the over-all order of the reaction is simply n = α + β + ----- (2) Such a reaction is said to be of the αth order with respect to the substance A, the βth order with respect to B.In the following questions, a statement of Assertion followed by a statement of Reason is given. Choose the correct answer out of the following choices on the basis of the above passage.Assertion: Reactions can occur at different speeds.Reason: Rate of reaction is also called speed of reaction.

View answer

Most of the ores available in nature contain large amount of impurities i.e. gangue. The pretreatment of ores, based on physical properties and without bringing out any major chemical change in the ore is called ore dressing or ore concentration.Q.In the purification of bauxite by leaching, the chemicals employed in Baeyer’s and Hall’s process respectively area)Na2CO3 and NaOHb)NaOH andNa2CO3c)NaOH and C + N2d)Na2CO3 and NaCNCorrect answer is option 'B'. Can you explain this answer?

Share with a Friend

Answer this doubt

Question Description
Most of the ores available in nature contain large amount of impurities i.e. gangue. The pretreatment of ores, based on physical properties and without bringing out any major chemical change in the ore is called ore dressing or ore concentration.Q.In the purification of bauxite by leaching, the chemicals employed in Baeyer’s and Hall’s process respectively area)Na2CO3 and NaOHb)NaOH andNa2CO3c)NaOH and C + N2d)Na2CO3 and NaCNCorrect answer is option 'B'. Can you explain this answer? for Class 12 2024 is part of Class 12 preparation. The Question and answers have been prepared according to the Class 12 exam syllabus. Information about Most of the ores available in nature contain large amount of impurities i.e. gangue. The pretreatment of ores, based on physical properties and without bringing out any major chemical change in the ore is called ore dressing or ore concentration.Q.In the purification of bauxite by leaching, the chemicals employed in Baeyer’s and Hall’s process respectively area)Na2CO3 and NaOHb)NaOH andNa2CO3c)NaOH and C + N2d)Na2CO3 and NaCNCorrect answer is option 'B'. Can you explain this answer? covers all topics & solutions for Class 12 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for Most of the ores available in nature contain large amount of impurities i.e. gangue. The pretreatment of ores, based on physical properties and without bringing out any major chemical change in the ore is called ore dressing or ore concentration.Q.In the purification of bauxite by leaching, the chemicals employed in Baeyer’s and Hall’s process respectively area)Na2CO3 and NaOHb)NaOH andNa2CO3c)NaOH and C + N2d)Na2CO3 and NaCNCorrect answer is option 'B'. Can you explain this answer?.

Solutions for Most of the ores available in nature contain large amount of impurities i.e. gangue. The pretreatment of ores, based on physical properties and without bringing out any major chemical change in the ore is called ore dressing or ore concentration.Q.In the purification of bauxite by leaching, the chemicals employed in Baeyer’s and Hall’s process respectively area)Na2CO3 and NaOHb)NaOH andNa2CO3c)NaOH and C + N2d)Na2CO3 and NaCNCorrect answer is option 'B'. Can you explain this answer? in English & in Hindi are available as part of our courses for Class 12. Download more important topics, notes, lectures and mock test series for Class 12 Exam by signing up for free.

Here you can find the meaning of Most of the ores available in nature contain large amount of impurities i.e. gangue. The pretreatment of ores, based on physical properties and without bringing out any major chemical change in the ore is called ore dressing or ore concentration.Q.In the purification of bauxite by leaching, the chemicals employed in Baeyer’s and Hall’s process respectively area)Na2CO3 and NaOHb)NaOH andNa2CO3c)NaOH and C + N2d)Na2CO3 and NaCNCorrect answer is option 'B'. Can you explain this answer? defined & explained in the simplest way possible. Besides giving the explanation of Most of the ores available in nature contain large amount of impurities i.e. gangue. The pretreatment of ores, based on physical properties and without bringing out any major chemical change in the ore is called ore dressing or ore concentration.Q.In the purification of bauxite by leaching, the chemicals employed in Baeyer’s and Hall’s process respectively area)Na2CO3 and NaOHb)NaOH andNa2CO3c)NaOH and C + N2d)Na2CO3 and NaCNCorrect answer is option 'B'. Can you explain this answer?, a detailed solution for Most of the ores available in nature contain large amount of impurities i.e. gangue. The pretreatment of ores, based on physical properties and without bringing out any major chemical change in the ore is called ore dressing or ore concentration.Q.In the purification of bauxite by leaching, the chemicals employed in Baeyer’s and Hall’s process respectively area)Na2CO3 and NaOHb)NaOH andNa2CO3c)NaOH and C + N2d)Na2CO3 and NaCNCorrect answer is option 'B'. Can you explain this answer? has been provided alongside types of Most of the ores available in nature contain large amount of impurities i.e. gangue. The pretreatment of ores, based on physical properties and without bringing out any major chemical change in the ore is called ore dressing or ore concentration.Q.In the purification of bauxite by leaching, the chemicals employed in Baeyer’s and Hall’s process respectively area)Na2CO3 and NaOHb)NaOH andNa2CO3c)NaOH and C + N2d)Na2CO3 and NaCNCorrect answer is option 'B'. Can you explain this answer? theory, EduRev gives you an ample number of questions to practice Most of the ores available in nature contain large amount of impurities i.e. gangue. The pretreatment of ores, based on physical properties and without bringing out any major chemical change in the ore is called ore dressing or ore concentration.Q.In the purification of bauxite by leaching, the chemicals employed in Baeyer’s and Hall’s process respectively area)Na2CO3 and NaOHb)NaOH andNa2CO3c)NaOH and C + N2d)Na2CO3 and NaCNCorrect answer is option 'B'. Can you explain this answer? tests, examples and also practice Class 12 tests.

Explore Courses for Class 12 exam