Only One Option Correct Type
Direction (Q. Nos. 1-30) This section contains 30 multiple choice questions. Each question has four choices (a), (b), (c) and (d), out of which ONLY ONE is correct.
The most electropositive metals are isolated from their ores by
Metals like Na, K, Mg, Ca, Al extracted by the electrolysis of their salts in molten state. This is called electrometallurgy.
Which of the following does not involve heating?
Leaching This method consists in treating the powdered ore with a suitable reagent (acids, bases or other chemicals) which can selectively dissolve the ore but not the impurities.
Which is incorrectly matched?
Chalcocite = Copper glance = CU2S.
Magnesium is extracted from sea water by Dow process. In this process to separate Mg, the process carried is
Roasted iron ore is mixed with coke and lime stone and smelted in blast furnace. Which among the following does not represent the correct answer about the reactions taking place in the blast furnace?
CaCO3 → CaO + CO2,CaO + SiO2 (slag)
Zone refining is based on the principle of
Zone refining is based on the principle that the impurities are more soluble in the melt than in the solid state of the metal.
Addition of high proportions of m anganese makes steel useful in m aking rails of railroads, because manganese
(I) gives hardness to steel
(II) helps the forri^tion of oxides of iron
(III) can remove oxygen and sulphur
(IV) can show highest oxidation state of +7
Manganese steel, an alloy of exceptional durability that found uses in the construction of railroad rails and rock-crushing machinery. Manganese steel containing 12-14 per cent manganese, it provides a hard, wear-resistant etc.
Among the following group of oxides, the group that cannot be reduced by carbon to give the respective metals
CuO, K2O cannot be reduced to give respective metals.
Selection of temperature to carry out a reduction process depends so as to make
The reduction process is accompanied by an increase in volume and is therefore facilitated when implemented under reduced pressure condition. Hence, ΔG is positive.
The common impurities present in the bauxite ore are
The major impurities in bauxite are iron oxides (haematite), silicon dioxide.
The major role of fluorspar (CaF2) which is added in small quantity in the electrolytic reduction of alumina dissolved in fused cryolite (Na3AIF6) is/are
Fluorspas (CaF2) is used to lower the temperature of the melt. It is also used to increase the conductivity of the mixture.
Which of the following is not the correct process ?
2AI + Fe2O3 → AI2O3 + 2Fe
In the extraction of Ag and Au using a KCN solution, cyanide ions react with metal ions as
Which of the following are correctly matched ?
Cyanide process Extraction of Au, Ag
Which of the following minerals do not contain lead ?
Heavy spar is BaSO4, Anglesite = PbCO3
Cerussite = PbSO4, Galena = PbS
Spiegel (or) spiegeleise'n, used in the manufacture of steel by the Bessemer process, is an alloy of
Spiegeleisen is a ferromanganese alloy containing approximately 15% manganese and small quantities of carbon and silicon. Historically, this was the standard form in which manganese was traded and used in steel making.
Being remarkably free from impurities, such as phosphorus, sulphur, and silica, it was much used in the Bessemer process for the purpose of reintroducing carbon. It reduces the iron oxide and is itself subject to oxidation.
Among the following statements the incorrect one is
Argentite (Ag2S) is sulphide and cuprite are oxides.
In the commercial electrochemical process for aluminium extraction the electrolyte used is
The molten mixture of Al2O3 and Na3AIF6 used as an electrolyte.
The metal that cannot be obtained by electrolysis of an aqueous solution of its salt is
Aqueous solution of calcium chloride upon electrolysis give calcium hydroxide because calcium metal reacts with water to produce calcium hydroxide.
When a metal is precipitated by adding a more electropositive metal, then the process is called
Hydrometallurgy is the process of bringing the metal into solution by the action of suitable chemical reagents (NaCN solution or chlorine in water etc.) followed by recovery of the metal by the use of proper precipitating agent which is a more electropositive metal.
In the extraction of lead the Parke’s process is used to remove the metal
Argentiferrous lead contain upto 2% silver in it. To remove such silver in lead in desilverisation methods are used like Parke’s and Pattinson's process. In this zinc is added which combine with Ag forming zinc-silver alloy which is lighter and separated.
In which of the following isolations no reducing agent is required ?
Cinnabar (HgS) on roasting from HgO which is unstable (due to + ve ΔH°f) at high temperature and de compose forming the metal.
Which of the following reaction(s) does not occur in Bessemers convertor ?
Except the first one ail other reactions occur.
Refactory materials are generally used in furnaces because
Furnaces are lined with refactries which are resistant to different chemicals, withstand high temperature and loads etc.
In the leaching of Ag2S with NaCN , a stream of air is also passed. It is because of
4Na2S + 5O2 + 2 H2O → 2 Na2SO4 + 4NaOH + S
Which is used to extract zinc?
The zinc ores are sphalerite (ZnS) and ZnCO3.
Identify x, y, z in the following process ; Metal sulphid impure metal pure metal
The sequence of steps should be roasting, reduction and electrolytic refining.
Element carbon is most likely to reduce Fe2O3 in which of the following temperature ranges ?
The uppermost part of the furnace where the temperature is 250-700°C haematite is reduced by CO whereas carbon is effective as reducing agent at high temperature.
The reverberatory furnace used for preparation of wrought iron, its hearth is lined with
To eliminate carbon impurities furnace is lined with heamatite.
The electrolyte used in Castner’s process of sodium extraction is
To extract aqueous solution should not be used, only molten chemical should be used.