Description : Assertion : Zone refining method is very useful for producing semiconductors. Reason : Semiconductors are of high purity.
Last Answer : Assertion : Zone refining method is very useful for producing semiconductors. Reason : Semiconductors are of high purity.
Description : The ultrapure metal is obtained by - (1) Calcination (2) Sublimation (3) zone refining (4) None of these
Last Answer : (3) zone refining Explanation: The principal stages in the production of ultrapure metals are the preparation of pure chemical compounds, the reduction of the compounds to the elementary state and further purification.
Description : The correct sequence of steps involved in extraction of metal from its ore is a) removal of impurities, purify metal, reduction of ore b) purify metal, removal of impurities, reduction of metal ore . c ... of metal , reduction d) removal of impurities from ore , reduction of ore , refining of metal
Last Answer : d) removal of impurities from ore , reduction of ore , refining of metal
Description : The method of zone refining of metals is based on the principle of :
Last Answer : The method of zone refining of metals is based on the principle of : A. Greater mobility of the ... the impurity in the molten state than in the solid
Description : Pick up the correct statement from the following: (A) Quick lime is obtained by burning pure lime stone (B) Hydraulic lime is obtained by burning lime stone containing clay 5% to 30% (C) Poor lime is obtained by burning lime stone containing impurities more than 5% (D) All the above
Last Answer : Answer: Option D
Description : High purity copper metal is obtained by
Last Answer : High purity copper metal is obtained by A. carbone reduction B. Hydrogen reduction C. ... from Bessomer converter is called as blister copper.
Description : In electro-refining, the pure metal is deposited on – (1) vessel (2) electrolyte (3) cathode (4) anode
Last Answer : (3) cathode Explanation: In electro-refining, the anodes consist of unrefined impure metal, and as the current passes through the acidic electrolyte the anodes are corroded into the solution so ... pure metal onto the cathodes. Electrolytic refining is used to extract impurities from crude metals.
Description : During electro refining, Pure Metal is collected at
Last Answer : Cathode
Description : In electro-refining, the pure metal is deposited on (1) vessel (2) electrolyte (3) cathode (4) anode
Last Answer : cathode
Description : Explain the process of zone refining. Name one metal refined by this method.
Last Answer : The apparatus used for zone refining consists of a circular heater fitted around the rod of impure metal at one end. The circular heater is slowly moved to the other end. At the heated zone, ... in solid metal passes into the adjacent molten part. A metal refined by zone refining is germanium.
Description : Refining process of impure metals depends upon the differences in properties of the metal. Extraction of Al is usually carried out from its bauxite or
Last Answer : Refining process of impure metals depends upon the differences in properties of the metal. ... . leaching C. liquation D. magnetic seperation
Last Answer : Refining process of impure metals depends upon the differences in properties of the metal. Extraction of Al is usually ... A D. I-D,II-A,III-C,IV-B
Description : With increase in impurities in metals, their corrosion resistances (A) Increase (B) Decrease (C) Remain same (D) May increase or decrease; depending on the type of metal
Last Answer : (B) Decrease
Description : . In contact process, SO3 is absorbed in 97% H2SO4 and not in water, because (A) SO3 gas is sparingly soluble in water (B) Water forms an acid mist, which is difficult to absorb (C) The purity of acid is affected (D) Scale formation in the absorber is to be avoided
Last Answer : (B) Water forms an acid mist, which is difficult to absorb
Description : Pick out the wrong statement. (A) A soft magnetic material should have high permeability and small area of hysteresis loop (B) Poisson's ratio of high melting point metals is more than unity (C) ... less than 185°C (D) Steel produced by B.O.F process is ideally suited for manufacturing flat product
Last Answer : Option B
Description : Crude oil is subjected to vacuum distillation in the last stage, because (A) High boiling point products like heavy fuel oil & lubricating oils are heat sensitive and may decompose (B) Lighter/low ... prone to thermal decomposition (C) High purity products can be obtained thereby (D) None of these
Last Answer : (A) High boiling point products like heavy fuel oil & lubricating oils are heat sensitive and may decompose
Description : Zone refining is based on the principle of
Last Answer : Zone refining is based on the principle of A. fractional distillation B. fractional ... C. partition coefficent D. chromatographic seperation
Description : Zone refining is based on the principle that
Last Answer : Zone refining is based on the principle that A. impurities of low boiling metals can be ... volatile compound can be decomppose in pure metal.
Description : Zone refining is a method to obtain
Last Answer : Zone refining is a method to obtain A. very high temperature B. ultra pure Al C. ultra pure metals D. ultra pure oxides
Description : Zone refining method is used for refining
Last Answer : Zone refining method is used for refining A. Al B. Ge C. Cu D. Fe
Description : Copper is refined by - (1) roasting (2) oxidation (3) electrolysis (4) zone refining
Last Answer : (1) roasting Explanation: Copper is refined by the method of roasting. In the roaster, the copper concentrate is partially oxidised to produce "calcine" and sulfur dioxide gas. In roasting, the ... ore concentrate is treated with very hot air. This process is generally applied to sulphide minerals.
Description : Zone refining is used for the purification of?
Last Answer : Ge
Description : What is meant by zone refining or fractional crystallization?
Last Answer : Zone refining is a technique of obtaining ultra pure metal. It is based on the principle of differences in solubility of impurities in liquid and solid states of the metal.
Description : What is the Principle of Zone refining ?
Last Answer : Ans. : When the molten solution of an impure metal is allowed to cool, the pure metal crystallizes out while the impurities remains in the solution.
Description : By which process copper is refined ------? A. Roasting (Answer) B. Oxidation C. Zone Refining D. Electrolysis
Last Answer : A. Roasting (Answer)
Description : Copper is refined by (1) roasting (2) oxidation (3) electrolysis (4) zone refining
Last Answer : roasting
Description : Elecyroltic refining is used to purify which of the following metals?
Last Answer : Elecyroltic refining is used to purify which of the following metals? A. Cu and Zn B. Ge and Si C. Zr and Ti D. Zn and Hg
Description : The process of extraction of metals from their ores; and then refining them for use is known as?
Last Answer : metallurgy
Description : Which of the following metals is not subjected to electrolytic refining/purification? (A) Copper (B) Zinc (C) Tin (D) Aluminium
Last Answer : (C) Tin
Description : Low purity oxygen is used for (A) L.D. steel making (B) Cutting and welding of metals (C) Medicinal purposes (D) Chemical oxidation processes
Last Answer : (D) Chemical oxidation processes
Description : Inorganic impurities causing water pollution is (A) Fats (B) Carbohydrates (C) Salts of metals (D) Protein
Last Answer : (C) Salts of metals
Description : What alloy is created when you melt and mix all metals on the periodic table in equal portions?
Last Answer : You can’t mix them all, their melting points are vastly different.
Description : Trinitrotoluene is – (1) used to melt metals (2) used to fuse two metals (3) used as an abrasive (4) used as an explosive
Last Answer : (4) used as an explosive Explanation: Trinitrotoluene (C6H2 (NO2)3.CH3), abbreviated as TNT, is sometimes used as a reagent in chemical synthesis, but it is best known as an explosive material ... The explosive yield of TNT is considered to be the standard mea-sure of bombs and other explosives.
Description : Trinitrotoluene is (1) used to melt metals (2) used to fuse two metals (3) used as an abrasive (4) used as an explosive
Last Answer : used as an explosive
Description : Ultrapure elements are obtained in the following method of mental refining
Last Answer : Ultrapure elements are obtained in the following method of mental refining A. Electrolysis B. Poling C. Liquation D. Distallation
Description : The purity of `H_(2)SO_(4)` obtained by contact process is
Last Answer : The purity of `H_(2)SO_(4)` obtained by contact process is A. `96-98%` B. `92-96%` C. `92-94%` D. `100%`
Description : Cast iron (A) Is obtained by purifying pig iron (B) Is manufactured in required shapes (C) May contain 2 to 5 per cent of carbon with other impurities (D) All the above
Description : Purity of a metal can be determined with the help of – (1) Pascal's law (2) Boyle's law (3) Archimedes principle (4) Conservation of mass principle
Last Answer : (3) Archimedes principle Explanation: Purity of a metal can be determined with the help of Archimedes Principle which makes use of the densities and buoyancy of metals. Finding the density of a metal ... help to determine its purity. It is most commonly used in the checking the purity of gold.
Description : Purity of a metal can be determined with the help of (1) Pascal’s law (2) Boyle’s law (3) Archimedes principle (4) Conservation of mass principle
Last Answer : Archimedes principle
Description : Give reason for the following: (i)alkali metals do not occur free in nature. (ii)alkali metals have low I .E. (iii)LiI is more soluble than KI in ethanol.
Last Answer : Ans.(i)They are highly reactive in natur (ii) Because of large atomic size. (III)LiI is more covalent in character than KI
Description : Nitrogen 1. Is non-essential for the animal bodies 2. In air dilutes oxygen which, otherwise, is very active in the pure form 3. Makes oxygen soluble in blood 4. Is present in DNA and RNA The correct statements are: (a) 1 and 4 only (b) 2 and 4 only (c) 3 and 4 only (d) 1 and 2 only
Last Answer : Ans:(b)
Description : Co-current absorbers are usually used when the gas to be dissolved in the liquid is (A) Sparingly soluble (B) Highly soluble (C) A pure substance (D) A mixture
Last Answer : (C) A pure substance
Description : When the gas to be dissolved in liquid is a/an __________ then normally co-current adsorber are used. (A) Mixture of two gases (B) Pure gas (C) Ideal gas (D) Sparingly soluble gas
Last Answer : (B) Pure gas
Description : Humidification involves mass transfer between a pure liquid phase and a fixed gas, which is (A) Insoluble in the liquid (B) Soluble in the liquid (C) Non-ideal in nature (D) At a fixed temperature
Last Answer : (A) Insoluble in the liquid
Description : Flux addition during smelting of ore is done to (A) Remove impurities/gangue (B) Enhance rate of reaction (C) Accelerate reduction of ore (D) Separate slag from metal
Last Answer : (A) Remove impurities/gangue
Description : Impurities in metal ores are called: w) flux x) gangue (pron: gang) y) slag z) sediments
Last Answer : ANSWER: X -- GANGUE
Last Answer : Na and k metal carbonates are soluble in water
Description : Presence of __________ in water stream are deleterious to aquatic life. (A) Soluble and toxic organics (B) Suspended solids (C) Heavy metals and cyanides (D) All (A), (B) & (C)
Last Answer : (D) All (A), (B) & (C)
Description : Which one of the following metals is immune to corrosion by air, water, hydrochloric acid and nitric acid; but is soluble in aqua regia? w) gold x) silver y) magnesium z) nickel
Last Answer : ANSWER: W -- GOLD
Description : Name the following: (a) A metal, which is preserved in kerosene. (b) A lustrous coloured non-metal. (c) A metal, which can melt while kept on palm. (d) A metal, which is a poor conductor of heat. -Chemistry
Last Answer : a) Sodium is preserved in kerosene. (b) Iodine is lustrous coloured non-metal. (c) Gallium. ‘ (d) Lead.