Electrochemical corrosion can occur, only if __________ is present in contact with metal. (A) Air (B) Oxygen (C) Liquid medium (D) Gaseous medium

Electrochemical corrosion can occur, only if __________ is present in contact with metal.
(A) Air
(B) Oxygen
(C) Liquid medium
(D) Gaseous medium
by

1 Answer

Answer :

(C) Liquid medium
by

Related questions

The deterioration of a metal by an electrochemical process is commonly termed as – (1) Erosion (2) Corrosion (3) Passivation (4) Abrasion

Description : The deterioration of a metal by an electrochemical process is commonly termed as – (1) Erosion (2) Corrosion (3) Passivation (4) Abrasion

Last Answer : (2) Corrosion Explanation: Corrosion can be defined as the deterioration of materials by chemical processes.

The deterioration of a metal by an electrochemical process is commonly termed as (1) Erosion (2) Corrosion (3) Passivation (4) Abrasion

Description : The deterioration of a metal by an electrochemical process is commonly termed as (1) Erosion (2) Corrosion (3) Passivation (4) Abrasion

Last Answer : Corrosion

Corrosion involves exchange of electrons in __________ corrosion. (A) Chemical (B) Electrochemical (C) Both (A) & (B) (D) Neither (A) nor (B)

Description : Corrosion involves exchange of electrons in __________ corrosion. (A) Chemical (B) Electrochemical (C) Both (A) & (B) (D) Neither (A) nor (B)

Last Answer : (C) Both (A) & (B)

Alloy powder manufactured by the following process have spherical shapes. (A) Electrochemical deposition (B) Gaseous reduction (C) Atomisation (D) Mechanical attrition

Description : Alloy powder manufactured by the following process have spherical shapes. (A) Electrochemical deposition (B) Gaseous reduction (C) Atomisation (D) Mechanical attrition

Last Answer : (C) Atomisation

Though tin occurs lower than iron in the electrochemical series, yet it is coated on steel for corrosion protection, because of its (A) Lower cost (B) Abundant availability (C) Resistance to vegetable acids as the tin plate are commercially used in 'canning' industry (D) None of these

Description : Though tin occurs lower than iron in the electrochemical series, yet it is coated on steel for corrosion protection, because of its (A) Lower cost (B) Abundant availability (C) Resistance to vegetable acids as the tin plate are commercially used in 'canning' industry (D) None of these

Last Answer : (C) Resistance to vegetable acids as the tin plate are commercially used in 'canning' industry

The chemistry of corrosion of iron is essentially an electrochemical phenomenon. Explain the reactions occurring during the corrosion of iron in the atmosphere. -Chemistry

Description : The chemistry of corrosion of iron is essentially an electrochemical phenomenon. Explain the reactions occurring during the corrosion of iron in the atmosphere. -Chemistry

Last Answer : The mechanism of corrosion is explained on the basis of electrochemical theory. By taking example of rusting of iron, we Refer tothe formation of small electrochemical cells on the surface of iron. The redox reaction involves ... net resultant Redox reaction is 2Fe(s) + O2 (g) + 4H+ → 2Fe2+ + 2H2O

Define electrochemical corrosion.

Description : Define electrochemical corrosion.

Last Answer : Electrochemical corrosion:- The corrosion which is brought about through ionic reactions in the presence of moisture or solution as a conducting medium when two dissimilar metals are in contact with each other is called electro chemical corrosion. 

Name any four factors affecting electrochemical corrosion.

Description : Name any four factors affecting electrochemical corrosion.

Last Answer : A) Nature of metal:  1) Position of metal in a galvanic series: A metal having higher position in a galvanic series has more chemical reactivity and therefore, it gets attacked by gaseous and ... as a conducting medium and promotes corrosion. e.g:- Rusting of Fe is promoted in humid atmosphere.

Gasification of the solid fuel converts its organic part into combustible by interaction with air/oxygen and steam so as to obtain a secondary gaseous fuel of high calorific value having no ash. Gasification reactions are normally carried out at about __________ °C. (A) 400-500 (B) 900-1000 (C) 1400-1500 (D) 1700-1800

Description : Gasification of the solid fuel converts its organic part into combustible by interaction with air/oxygen and steam so as to obtain a secondary gaseous fuel of high calorific value having no ash. Gasification reactions are ... __________ °C. (A) 400-500 (B) 900-1000 (C) 1400-1500 (D) 1700-1800

Last Answer : (B) 900-1000

Which one can be directly solidified from gaseous state without entering into liquid state? (A) Helium (B) Oxygen (C) Carbon dioxide (D) None of these

Description : Which one can be directly solidified from gaseous state without entering into liquid state? (A) Helium (B) Oxygen (C) Carbon dioxide (D) None of these

Last Answer : (C) Carbon dioxide

Corrosion rate cannot be lowered by reducing the __________ of the corroding medium. (A) Concentration (B) Velocity (C) Temperature (D) None of these

Description : Corrosion rate cannot be lowered by reducing the __________ of the corroding medium. (A) Concentration (B) Velocity (C) Temperature (D) None of these

Last Answer : (A) Concentration

_________________ is the name given to a gaseous phase that is in contact with the liquid phase, or that is in the vicinity of a state where some of it might be condensed.  a) Vapor  b) Saturated Vapor  c) Superheated Vapor  d) Wet Vapor

Description : _________________ is the name given to a gaseous phase that is in contact with the liquid phase, or that is in the vicinity of a state where some of it might be condensed.  a) Vapor  b) Saturated Vapor  c) Superheated Vapor  d) Wet Vapor

Last Answer : Vapor

Pick out the correct statement. (A) Stainless steel is nothing but chromium coated steel (B) Hardening of a soft metal can be done by alloying it with another metal or non-metal (C) Plastic deformation of a material is its temporary distortion under the action of applied stress (D) Rusting of iron is not electrochemical in nature

Description : Pick out the correct statement. (A) Stainless steel is nothing but chromium coated steel (B) Hardening of a soft metal can be done by alloying it with another metal or non-metal (C) ... its temporary distortion under the action of applied stress (D) Rusting of iron is not electrochemical in nature

Last Answer : (B) Hardening of a soft metal can be done by alloying it with another metal or non-metal

Electrometallurgical methods of metal extraction is normally used for those metals (A) Whose oxide/ore is not reduced by carbon (B) Which fall in the category of alkali & alkaline earth metals (C) Which stands higher in the electrochemical series of the metal (D) All (A), (B) & (C)

Description : Electrometallurgical methods of metal extraction is normally used for those metals (A) Whose oxide/ore is not reduced by carbon (B) Which fall in the category of alkali & alkaline earth metals (C) Which stands higher in the electrochemical series of the metal (D) All (A), (B) & (C)

Last Answer : (D) All (A), (B) & (C)

Oxygen percentage in the flue gas coming out of a gaseous fuel fired furnace should be ideally about __________ percent. (A) < 2 (B) < 5 (C) < 8 (D) < 10

Description : Oxygen percentage in the flue gas coming out of a gaseous fuel fired furnace should be ideally about __________ percent. (A) < 2 (B) < 5 (C) < 8 (D) < 10

Last Answer : (A) < 2

Presence of __________ in a dry gaseous fuel does not contribute to its calorific value. (A) Sulphur (B) Oxygen (C) Hydrogen (D) Carbon

Description : Presence of __________ in a dry gaseous fuel does not contribute to its calorific value. (A) Sulphur (B) Oxygen (C) Hydrogen (D) Carbon

Last Answer : (B) Oxygen

Write the mechanism of corrosion of metal due to action of oxygen.

Description : Write the mechanism of corrosion of metal due to action of oxygen.

Last Answer : Mechanism: Metallic surfaces when exposed to air undergo oxidation and the process of corrosion is represented by the equation.   A thin oxide layer is formed on the metal surface and the nature of this film decides further action depending upon the film so produced.   

Bomb calorimeter is used for the determination of calorific value of the __________ fuels. (A) Gaseous (B) Solid(C) Liquid(D) Both (B) and (C)

Description : Bomb calorimeter is used for the determination of calorific value of the __________ fuels. (A) Gaseous (B) Solid (C) Liquid (D) Both (B) and (C)

Last Answer : (D) Both (B) and (C)

Pick out the wrong statement. (A) High concentration of oxygen in flue gas means high stack loss (B) Gaseous fuels require the least % excess air for complete combustion (C) The ratio of fixed carbon to volatile matter percentage in coal is called its 'fuel ratio' (D) Calorific value of natural gas is more than that of LPG

Description : Pick out the wrong statement. (A) High concentration of oxygen in flue gas means high stack loss (B) Gaseous fuels require the least % excess air for complete combustion (C) The ratio of fixed carbon to ... coal is called its 'fuel ratio' (D) Calorific value of natural gas is more than that of LPG

Last Answer : (D) Calorific value of natural gas is more than that of LPG

A liquid/gaseous fuel containing hydrocarbons and high amount of sulphur is burnt with 40% excess air. The flue gas still contains large amount of carbon monoxide. This may be due to the (A) Presence of large quantity of hydrogen in the fuel (B) Low calorific value of the fuel (C) High sulphur content in the fuel (D) Lack of thorough mixing of fuel with air

Description : A liquid/gaseous fuel containing hydrocarbons and high amount of sulphur is burnt with 40% excess air. The flue gas still contains large amount of carbon monoxide. This may be due to the (A) Presence of large ... fuel (C) High sulphur content in the fuel (D) Lack of thorough mixing of fuel with air

Last Answer : (D) Lack of thorough mixing of fuel with air

The optimum percentage of excess air for combustion depends upon the__________ of the fuel.(A) Type (solid, liquid or gaseous)(B) Calorific value(C) Sulphur content(D) Ignition temperature

Description : The optimum percentage of excess air for combustion depends upon the__________ of the fuel. (A) Type (solid, liquid or gaseous) (B) Calorific value (C) Sulphur content (D) Ignition temperature

Last Answer : (A) Type (solid, liquid or gaseous)

White smoke coming out of the chimney of a furnace indicates the useof(A) Low excess air(B) Very high excess air(C) Gaseous fuel in the furnace(D) Liquid fuel in the furnace

Description : White smoke coming out of the chimney of a furnace indicates the useof (A) Low excess air (B) Very high excess air (C) Gaseous fuel in the furnace (D) Liquid fuel in the furnace

Last Answer : (B) Very high excess air

Pick out the wrong statement. (A) Strongly caking coal should not be used in the Lurgi gasifier (B) Acetylene gas cannot be used for illumination purpose (C) Water gas is called blue gas because of the color of the flame, when it is burnt (D) Gaseous fuels require less percentage of excess air for combustion as compared to liquid fuels

Description : Pick out the wrong statement. (A) Strongly caking coal should not be used in the Lurgi gasifier (B) Acetylene gas cannot be used for illumination purpose (C) Water gas is called blue gas ... is burnt (D) Gaseous fuels require less percentage of excess air for combustion as compared to liquid fuels

Last Answer : (B) Acetylene gas cannot be used for illumination purpose

Enzymes are organic catalysts used in the __________ reactions. (A) Chemical (B) Biochemical (C) Photochemical (D) Electrochemical

Description : Enzymes are organic catalysts used in the __________ reactions. (A) Chemical (B) Biochemical (C) Photochemical (D) Electrochemical

Last Answer : (B) Biochemical

During electrolysis of aqeous solution of NaCl, there are two type of anions are present Cl- and –OH, Cl- is discharged first than –OH,although it is present below Cl- in electrochemical series. Give reason.

Description : During electrolysis of aqeous solution of NaCl, there are two type of anions are present Cl- and –OH, Cl- is discharged first than –OH,although it is present below Cl- in electrochemical series. Give reason.

Last Answer : Ans: During this electrolysis process Chloride ions come from NaCl, which is a strong electrolyte and ionize to large extent so concentration of chloride ions in solution will be high. ... chloride ions it is first discharged despite of its presence above than hydroxyl in electrochemical series.

Why cation present below in electrochemical series can discharge before the elements present above them in an electrochemical cell?

Description : Why cation present below in electrochemical series can discharge before the elements present above them in an electrochemical cell?

Last Answer : Ans: This is because their ability to be reduced (reduction potential) is more than the cation present above them in electrochemical series. So they take electrons before the other cations and get discharged.

Separation of __________ employs gaseous diffusion process. (A) N2 and O2 from air (B) Isotopes of uranium (C) Isotopes of helium (D) SO2 and air

Description : Separation of __________ employs gaseous diffusion process. (A) N2 and O2 from air (B) Isotopes of uranium (C) Isotopes of helium (D) SO2 and air

Last Answer : (B) Isotopes of uranium

Preheating of __________ the flame temperature. (A) The gaseous fuel before combustion decreases (B) Combustion air decreases (C) Either the fuel or the air or both, increases (D) Either the fuel or the air does not affect

Description : Preheating of __________ the flame temperature. (A) The gaseous fuel before combustion decreases (B) Combustion air decreases (C) Either the fuel or the air or both, increases (D) Either the fuel or the air does not affect

Last Answer : (C) Either the fuel or the air or both, increases

Which of the following is not used as a medium for high temperature heating ? (A) Dowtherm (B) Mercury (C) Liquid metal (e.g. molten sodium) (D) Fused salts (e.g., an eutectic mixture of 53% KNO3 , 40% NaNO2and 7% NaNO3 )

Description : Which of the following is not used as a medium for high temperature heating ? (A) Dowtherm (B) Mercury (C) Liquid metal (e.g. molten sodium) (D) Fused salts (e.g., an eutectic mixture of 53% KNO3 , 40% NaNO2and 7% NaNO3 )

Last Answer : (B) Mercury

During combustion of a gaseous fuel, the presence of a non-luminous flame is an indication of the (A) Incomplete combustion (B) Complete combustion (C) High oxygen in flue gas (D) None of these

Description : During combustion of a gaseous fuel, the presence of a non-luminous flame is an indication of the (A) Incomplete combustion (B) Complete combustion (C) High oxygen in flue gas (D) None of these

Last Answer : (B) Complete combustion

A gaseous fuel in order to develop luminosity on burning, must contain (A) Carbon monoxide (B) Hydrocarbons (C) Hydrogen (D) Oxygen

Description : A gaseous fuel in order to develop luminosity on burning, must contain (A) Carbon monoxide (B) Hydrocarbons (C) Hydrogen (D) Oxygen

Last Answer : (B) Hydrocarbons

Reverse osmosis is normally used for the (A) Separation of isotopes of uranium from gaseous uranium hexafluoride (B) Separation of helium from natural gas (C) Desalination of brackish water to produce potable (drinking) water (D) Purification of oxygen

Description : Reverse osmosis is normally used for the (A) Separation of isotopes of uranium from gaseous uranium hexafluoride (B) Separation of helium from natural gas (C) Desalination of brackish water to produce potable (drinking) water (D) Purification of oxygen

Last Answer : (C) Desalination of brackish water to produce potable (drinking) water

The wetted wall tower is used to determine (A) Individual mass transfer co-efficient (M.T.C.) in gaseous system (B) M.T.C. of individual components in a liquid-liquid system (C) M.T.C. of liquid in liquid-gas system (D) The overall M.T.C. of the system

Description : The wetted wall tower is used to determine (A) Individual mass transfer co-efficient (M.T.C.) in gaseous system (B) M.T.C. of individual components in a liquid-liquid system (C) M.T.C. of liquid in liquid-gas system (D) The overall M.T.C. of the system

Last Answer : (A) Individual mass transfer co-efficient (M.T.C.) in gaseous system

Heat transfer rate to the charge/stock in a furnace does not depend upon the (A) Type of fuels viz. solid, liquid or gaseous (B) Flue gas temperature (C) Emissivity of refractory walls (D) Initial temperature of the charged stock

Description : Heat transfer rate to the charge/stock in a furnace does not depend upon the (A) Type of fuels viz. solid, liquid or gaseous (B) Flue gas temperature (C) Emissivity of refractory walls (D) Initial temperature of the charged stock

Last Answer : (A) Type of fuels viz. solid, liquid or gaseous

Wobbe index' is a characteristic of (A) Solid fuels (B) Gaseous fuels (C) Liquid fuels (D) Fat coals

Description : Wobbe index' is a characteristic of (A) Solid fuels (B) Gaseous fuels (C) Liquid fuels (D) Fat coals

Last Answer : (B) Gaseous fuels

In the context of the chemical process industries, the term BOD is normally associated with the (A) Characterisation of solid wastes (B) Organic concentration in gaseous effluents (C) Characterisation of liquid effluents (D) Characterisation of boiler feed water

Description : In the context of the chemical process industries, the term BOD is normally associated with the (A) Characterisation of solid wastes (B) Organic concentration in gaseous effluents (C) Characterisation of liquid effluents (D) Characterisation of boiler feed water

Last Answer : (C) Characterisation of liquid effluents

A batch reactor is suitable for (A) Achieving cent percent conversion of reactants into products (B) Large scale gaseous phase reactions (C) Liquid phase reactions(D) Obtaining uniform polymerisation products in highly exothermicreactions

Description : A batch reactor is suitable for (A) Achieving cent percent conversion of reactants into products (B) Large scale gaseous phase reactions (C) Liquid phase reactions (D) Obtaining uniform polymerisation products in highly exothermic reactions

Last Answer : (C) Liquid phase reactions

While dissolving a gas into a liquid at a constant temperature, the ratio of the concentration of the gas in the solution phase and in the gaseous phase is (A) Infinity (B) Unity (C) Constant (D) Negative

Description : While dissolving a gas into a liquid at a constant temperature, the ratio of the concentration of the gas in the solution phase and in the gaseous phase is (A) Infinity (B) Unity (C) Constant (D) Negative

Last Answer : (C) Constant

One of the methods of purification of leach liquor is ion exchange, which involves (A) Exchange between two liquid phases (B) Exchange between a gaseous phase and a liquid phase (C) Exchange between a liquid phase and an organic resin phase (D) Exchange between a solid phase and a gas phase

Description : One of the methods of purification of leach liquor is ion exchange, which involves (A) Exchange between two liquid phases (B) Exchange between a gaseous phase and a liquid phase (C) Exchange between a liquid phase and an organic resin phase (D) Exchange between a solid phase and a gas phase

Last Answer : (C) Exchange between a liquid phase and an organic resin phase

Corrosion in boilers can be prevented by (A) Deaeration of feed water (B) Enhancing pH of feed water by adding alkali (C) Feeding sodium sulphite or hydrazine phosphate to the boilers, which combines with oxygen and prevents corrosion (D) All (A), (B) and (C)

Description : Corrosion in boilers can be prevented by (A) Deaeration of feed water (B) Enhancing pH of feed water by adding alkali (C) Feeding sodium sulphite or hydrazine phosphate to the boilers, which combines with oxygen and prevents corrosion (D) All (A), (B) and (C)

Last Answer : (D) All (A), (B) and (C)

Use of water having dissolved oxygen in boilers promotes (A) Corrosion (B) Sequestration (C) Scale formation(D) None of these

Description : Use of water having dissolved oxygen in boilers promotes (A) Corrosion (B) Sequestration (C) Scale formation (D) None of these

Last Answer : (A) Corrosion

Explain the mechanism of corrosion in acidic medium.

Description : Explain the mechanism of corrosion in acidic medium.

Last Answer : Mechanism of corrosion in acidic medium. An acidic environment refers to an environment having a pH value of less than 7.Acidic environments are more prone to cause corrosion than alkaline and neutral environments. ... , If the acid used is HCl, then the corrosion product is FeCl2.  

Which of the following metals in not used for coating of the base metal to guard it against corrosion? (A) Lead (B) Cadmium (C) Magnesium (D) Aluminium

Description : Which of the following metals in not used for coating of the base metal to guard it against corrosion? (A) Lead (B) Cadmium (C) Magnesium (D) Aluminium

Last Answer : (C) Magnesium

A metallic alloy in general as compared to their pure metal components is (A) More corrosion resistant (B) Having higher melting point (C) Having lower hardness, reactivity and fusibility (D) Having lower electrical conductivity

Description : A metallic alloy in general as compared to their pure metal components is (A) More corrosion resistant (B) Having higher melting point (C) Having lower hardness, reactivity and fusibility (D) Having lower electrical conductivity

Last Answer : (A) More corrosion resistant

Pick out the wrong statement about coating/electroplating of metals. (A) Phosphate coating is used as an excellent base for paints & enamels (B) Phosphate coating is less corrosion resistant than chromate coating (C) The base metal to be electroplated is normally made the cathode of the electrolytic cell and coating metal is made the anode (D) Calorising is the process of coating steel with chromium

Description : Pick out the wrong statement about coating/electroplating of metals. (A) Phosphate coating is used as an excellent base for paints & enamels (B) Phosphate coating is less corrosion resistant than ... coating metal is made the anode (D) Calorising is the process of coating steel with chromium

Last Answer : (D) Calorising is the process of coating steel with chromium

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

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

In connection with corrosion of metals, passivation is the process that (A) Intensifies deterioration (B) Changes the composition of the metal (C) Inhibits further deterioration (D) None of these

Description : In connection with corrosion of metals, passivation is the process that (A) Intensifies deterioration (B) Changes the composition of the metal (C) Inhibits further deterioration (D) None of these

Last Answer : (C) Inhibits further deterioration

Damage to metal surface by mechanical action is called (A) Pitting (B) Corrosion (C) Erosion (D) None of these

Description : Damage to metal surface by mechanical action is called (A) Pitting (B) Corrosion (C) Erosion (D) None of these

Last Answer : Option C

In a gas-liquid shell and tube heat exchanger, the(A) Presence of a non-condensable gas decreases the condensing film co￾efficient (B) Gases under high pressure are routed through the tube side, because high pressure gases are corrosive in nature (C) Gases to be heated/cooled is normally routed through the shell side, because the corrosion caused by the cooling water or steam condensate remain localised to the tubes (D) All 'a', 'b' & 'c'

Description : In a gas-liquid shell and tube heat exchanger, the (A) Presence of a non-condensable gas decreases the condensing film co￾efficient (B) Gases under high pressure are routed through the tube side, because high pressure ... water or steam condensate remain localised to the tubes (D) All 'a', 'b' & 'c'

Last Answer : (D) All 'a', 'b' & 'c'

During the absorption of HCl gas in water (to produce liquid HCl), the gas is kept above dew point to (A) Increase the rate of absorption (B) Avoid corrosion (C) Reduce the cooling water circulation rate (D) None of these

Description : During the absorption of HCl gas in water (to produce liquid HCl), the gas is kept above dew point to (A) Increase the rate of absorption (B) Avoid corrosion (C) Reduce the cooling water circulation rate (D) None of these

Last Answer : (B) Avoid corrosion