Industrial chemistry Flashcards

1
Q

Factors to be considered in establishing chemical industries

A

Capital
Labour
Technology
Supply of raw materials
Transportation and market
Site of installation

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2
Q

Mg as a raw material

A

Extraction of Mg from sea water is more profitable
Other than Na+, Mg2+ is the most abundant cation in sea water
0.13% by weight is Mg in sea water

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3
Q

What process is used for extraction of Mg

A

Dow process

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4
Q

Major steps of Dow process

A
  1. Thermal decomposition of limestone or Dolomite to obtain CaO (using limestone is advantageous)
  2. Precipitation of Mg(OH)2
  3. Mg(OH)2 formed is filterd and removed and reacted with concentrated HCl to get MgCl2.
  4. The solution is heated strongly to vaporize water.
  5. solid formed is fused in the steel chambers where electrolysis is done and then it is electrolized
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5
Q

Temperature maintained in the dow process

A

700-800 C

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6
Q

Melting point of Mg

A

650 C

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7
Q

Uses of Mg

A

Production of aircrafts and vehicles
Production of alloys

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8
Q

Percentage yield of Mg in dow’s process

A

99.8

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9
Q

Caustic soda

A

NaOH

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10
Q

Basic process of caustic soda production

A

A pure concentrated solution of sodium chloride is called brine. NaOH is produced by electrolyzing a brine solution. As the by-products hydrogen gas and chloride gas are released at the cathode and the anode respectively.

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11
Q

Types of cells used to produce caustic soda and their common name

A

Chlor-alkali cells

a) Mercury cells
b) Diaphragm cells
c) Membrane cells

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12
Q

Major steps in membrane cell method

A
  1. Removal of contaminants (SO4 2-, Mg2+, Ca2+) from brine solution
  2. Electrolysis in Ti anode producing Cl2 and Na+
  3. Electrolysis of water in Ni cathode producing H2 and OH-
  4. Transportation of Na+ from anode to cathode through pores of the membrane.
  5. Evaporation of NaOH
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13
Q

Uses of NaOH

A
  1. Production of soap
  2. Production of paper, artificial silk and dyes
  3. Using as a strong base
  4. Precipitation of heavy metal as their hydroxides in waste water treatment.
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14
Q

Uses of Cl2

A
  1. Bleaching textiles, woods and paper pulp
  2. Purifying the drinking water
  3. Production of HC1
  4. Production of chlorinated rubber, insecticides, dyes and medicine
  5. Production of vinyl chloride required to produce polymers like PVC
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15
Q

Uses of H2

A
  1. Manufacture of HCl
  2. Production of NH3
  3. Production of margarine by hydrogenation of vegetable oil
  4. Using as a fuel
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16
Q

Basic process of making soap and raw materials

A

Raw materials are animal fat or plant oil, NaOH or KOH

triglycerides are subject to a hydrolysis reaction with caustic soda (saponification) forming glycerol and sodium salts of long chain carboxylic acids.

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17
Q

Processes of soap manufacturing and their major steps

A

Hot process and the cold process

In the cold process, soap and glycerol are not separated

Steps of hot process
1. Saponification
2. Removal of the by-product, glycerin
3. Purification
4. Finishing

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18
Q

Caustic potash

A

KOH

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19
Q

Saponification

A

Purified vegetable oil is mixed with NaOH or KOH. Glycerin are soap (RCOONa) are produced
System is maintained at 70 C

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20
Q

Removal of glycerin

A

To decrease the solubility of soap in the aqueous phase NaCl (brine) is added. Glycerin dissolves in the salt solution.

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21
Q

Purification

A

Wet soap with salt is centrifuged
NaCl content in soap decreases to 0.5% (w/w)
Citric acid, phosphoric acid or free fatty acids associated with coconut oil are added to neutralize sodium hydroxide

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22
Q

Finishing

A

Soap heated to about 120 C is sprayed into a low pressure zone in the form of small droplets. Finally fillers, colours and perfumes are added

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23
Q

TFM value of soap

A

TFM (Total Fatty Matter) means the total fatty matter presents in soap. It is the percentage of RCOONa (soap) present in a cake of soap.

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24
Q

TFM value of a cake of washing soap

A

54-56% and the rest is fillers

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25
Q

Detergents

A

do not precipitate in hard water. The main ingredients of artificial detergents is sodium alkylbenzenesulphonate.

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26
Q

Process used in the production of Na2CO3

A

Solvey process

27
Q

Raw materials of Solvey process

A

NH3 obtained through Haber process
CO2 obtained by the thermal decomposition of limestone
Brine solution

28
Q

Steps of Solvey Process

A

Ammonification
Carbonation
Separation of NaHCO3
Obtaining Na2CO3 by heating NaHCO3

29
Q

Countercurrent principle

A

Mixing reactants efficiently by sending the reactants in opposite directions is referred to as the countercurrent principle.

30
Q

Ammonification

A

First the brine solution is introduced from the top of the tower and ammonia gas is introduced from the bottom of the tower.Ammonification of brine is an exothermic process. It is important to maintain a low temperature.

31
Q

Carbonation

A

The brine solution saturated with ammonia is introduced from the top of the second tower while CO2 is introduced from the bottom. Reaction is exothermic and the tower is kept cool.

32
Q

Regeneration of NH3 in solvey process

A

NH4Cl which is a by-product is used to generate NH3. NH4Cl is reacted with CaO obtained by the decomposition of CaCO3

33
Q

Final by product of the Solvey process

A

CaCl2

34
Q

Uses of Na2CO3

A

1) Removal of hardness of water
2) Addition to improve cleaning action when producing soap and detergents.
3) Using as washing soda
4) Mixing to the wood pulp in paper industry
5) Production of glass

35
Q

Raw materials used in Haber-Bosch process

A

N2 gas and H2 gas are the main raw materials. N2 gas is separated by fractional distillation of liquefied atmospheric air. Therefore N2 gas has a production cost.
Hydrogen gas is obtained by cracking hydrocarbons

36
Q

Percentage of NH3 used for fertilisers

A

83%

more than 80% to produce urea

37
Q

The optimum industrial conditions employed for the Haber-Bosch process

A

temperature in the range 450-500 C,
a pressure of 250-300 atm,
iron catalyst and
K2O and Al2O3 as catalystic promoters.

38
Q

Uses of NH3

A
  1. Production of nitric acid, fertilizers and nylon
  2. Petroleum industry utilizes ammonia in neutralizing the acid constituents of crude oil
  3. Used in water and waste water treatment, such as pH control
  4. Used as a refrigerant
  5. Used in the rubber industry for the stabilization of natural and synthetic latex to prevent premature coagulation
39
Q

Raw materials of Ostwald method

A

ammonia gas, atmospheric air and water

40
Q

The optimum industrial conditions employed for the Ostwald process

A

Temperature 800-850
Pt/Rh catalyst

41
Q

Uses of nitric acid

A
  1. Making fertilizer and explosives
  2. Making nitrates essential for industries KNO3 – to produce gun power
    AgNO3 – photography
  3. Making aqua regia
  4. Cleaning surfaces when welding metals
42
Q

H2S2O7

A

Pyrosulfuric acid / oleum

43
Q

Why H2SO4 cannot be produced directly by adding water to SO3

A

Reaction between SO3 and H2O is highly exothermic and violent hence only a mist of H2SO4 will be produced.

44
Q

The optimum industrial conditions employed for the contact process

A

1 atm
400-500
V2O5 catalyst

45
Q

Basic steps of contact process

A

Liquid sulfur heated upto 140 and atmospheric air is supplied to the furnace
Formed SO2 is transferred to the reaction chamber with V2O5 catalyst surfaces
Conc.H2SO4 is sprayed onto SO3 forming oleum

46
Q

Uses of H2SO4

A
  1. Production of phosphate fertilizers
  2. Production of ammonium sulphate fertilizer
  3. Production of artificial fibers including rayon and plastics
  4. Production of detergents containing alkyl and aryl sulphonates 5. Production of dyes, explosives and medicines
  5. Production of battery acid
  6. Drying gases
47
Q

Main minerals containing Ti

A

Ilmenite (FeOTiO2) and rutile (TiO2)

48
Q

Sulfate process

A

Removal of FeO from ilmenite is called sulphate process.

49
Q

Production process of TiO2 and its main steps

A

Chloride process
1.Chlorination
2.Oxidation

50
Q

Overall reaction of the chlorination process and the temperature maintained

A

Before this process rutile and coke are dried by heating to 200-300
TiO2 + C + Cl2 —–> TiCl4(g) + CO2(g)
950

51
Q

Overall reaction of the oxidation process and the temperature maintained

A

TiCl4 (g) + O2(g) —–> TiO2 (s) + 2Cl2 (g)

1000

52
Q

Uses of TiO2

A
  1. TiO2 is white in colour. Therefore it is used as a pigment to obtain bright white colour in paint, plastic goods and paper. The high refractive index if TiO2 is also a reason for using it as a pigment.
  2. TiO2 is chemically inert. Therefore it is used as a pigment to give white colour to medicine and toothpaste.
  3. TiO2 is also used to produce substances applied to prevent sunburns in the skin due to UV radiations in solar rays. TiO2 prevents the reach of UV rays to the skin.
  4. It is used to make some solar cells.
53
Q

Raw materials essential for iron extraction

A
  • Iron ore
  • Limestone
  • Coke (coal)
  • Air
54
Q

Slag

A

Calcium silicate (CaSiO3) and calcium aluminate (Ca(AlO2)2) formed are called the slag. The density of the slag is lower than that of molten iron. Therefore liquid slag layer floats on molten iron. As the slag covers the surface of molten iron, the chances for molten iron to react with oxygen are less.

55
Q

Production of vinegar

A

Acetic acid is the active ingredient. Toddy is subject to continued microbial activity it is oxidized to acetic acid. Artificial vinegar is produced by diluting appropriately, the acetic acid obtained by the oxidation of ethanol produced from raw materials turned out by petroleum industry.

56
Q

Uses of ethanol

A

Solvent for perfumes and scents
Environmental-friendly renewable fuel source

57
Q

Highest ethanol percentage

A

96.5%
rectified spirit

58
Q

Fraction distillation

A

The distillation technique used to separate components which are miscible and have different boiling points from a mixture

59
Q

Methods of extracting essential oils

A

Steam distillation
Solvent extraction
Pressing

60
Q

Pressing method is rarely used because

A
  1. The yield is poor
  2. Oil gets mixed up with other organic substances
61
Q

Raw materials of biodiesel production

A

Non-volatile plant oils (triglycerides)
Methanol
NaOH is used as a catalyst

62
Q

Steps used in biodiesel production

A
  1. Free fatty acids and non-saponifiable compounds in the plant oils are removed
  2. NaOH catalyst is dissolved in methanol and the mixture is mixed with triglycerides
  3. Transesterification reaction produces biodiesel and glycerol
  4. Glycerol layer is separated
  5. By separating and heating the layers, methanol contained in them can be removed.
63
Q

Iron ore contains

A

Hematite Fe2O3
Magnetite Fe3O4

64
Q

Main components of cinnamon oil

A

Leaf – eugenol
Bark – cinnamaldehyde
Root – camphor
Main constitution of citronella oil – geraniol