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

1 Answer

Answer :

(A) Concentration

Related questions

Description : Corrosion of well pipes may not be reduced by  (A) Reducing the draw down and the pumping rate  (B) Reducing the flow velocity  (C) Using thicker pipes  (D) Using screens having larger area of openings 

Last Answer : (D) Using screens having larger area of openings 

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

Last Answer : (C) Liquid medium

Description : For a heterogeneous catalytic reaction (A) Free energy of activation is lowered in the presence of catalyst, which remains unchanged at the end of reaction (B) A relatively small amount of catalyst ... with the reactant (D) The surface of the catalyst does not play an important role during reaction

Last Answer : (A) Free energy of activation is lowered in the presence of catalyst, which remains unchanged at the end of reaction

Description : Other parameters remaining same, the recrystallisation temperature of an alloy is lowered, when (A) Strain rate is increased (B) Grain size is increased (C) Prior cold deformation is increased (D) Not affected by any of the above parameters

Last Answer : (A) Strain rate is increased

Description : The cooling effect in a cooling tower cannot be increased by (A) Increasing the air velocity over the wet surfaces (B) Reducing the humidity of entering air (C) Lowering the barometric pressure (D) None of these

Last Answer : (D) None of these

Description : Yield of urea can be increased with excess ammonia and higher pressure & temperature, but because of __________ this is normally not done. (A) Increased biuret formation (B) High corrosion rate (C) Increased cost of equipment (D) All (A), (B) & (C)

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

Description : Moist atmospheric air at high temperature (e.g., in summer) having high concentration of sulphur dioxide causes (A) Fading of dyes on textiles (B) Corrosion, tarnishing & soiling of metals (C) Reduced strength of textiles (D) All (A), (B) and (C)

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

Description : . In filtration, the use of 'filter aid' helps in (A) Reducing the filtration pressure (B) Accelerating the rate of filtration (C) Deplugging the filter medium (D) Enhancing the cake porosity in case of a dense impermeable cake

Last Answer : (C) Deplugging the filter medium

Description : In most of the mechanically agitated liquid-liquid extractors, baffles or horizontal compartmental plates are provided, which helps in (A) Reducing the axial mixing (B) Increasing the rate of extraction (C) Maintaining the concentration difference between the two phases (D) All 'a', 'b' & 'c'

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

Description : Pick out the wrong statement (A) A horizontal line on the humidity chart indicates the temperature changes at constant molal humidity (B) When water is cooled from 80 to 70°C by exposure ... & air cannot be increased by either reducing the mixture temperature or by increasing the total pressure

Last Answer : (D) Relative saturation of unsaturated mixture of water vapor & air cannot be increased by either reducing the mixture temperature or by increasing the total pressure

Description : Higher concentration of nitrogen dioxide in atmospheric air causes (A) Cancer (B) Bronchitis (C) Asphyxiation (D) Corrosion

Last Answer : (B) Bronchitis

Description : As the temperature is lowered towards the absolute zero, the value of ∂(∆F)/∂T, then approaches (A) Unity (B) Zero (C) That of the heat of reaction (D) Infinity

Last Answer : B) Zero

Description : As the temperature is lowered towards the absolute zero, the value of the quantity (∂∆F/∂T) approaches (A) Zero (B) Unity (C) Infinity (D) None of these

Last Answer : (A) Zero

Description : Boiling point of water gets lowered at high altitudes (e.g., hills), because (A) Temperature is low (B) Atmospheric pressure is low (C) Atmospheric pressure is high (D) None of these

Last Answer : Option B

Description : Zinc is highly __________ at room temperature. (A) Ductile (B) Resistant to atmospheric corrosion (C) Malleable (D) Brittle

Last Answer : (B) Resistant to atmospheric corrosion

Description : Metallic recuperators are not used for waste heat recovery, if the hot flue gas temperature is above __________ °C, because corrosion prevails at higher temperatures. (A) 350 (B) 750 (C) 1050 (D) 1250

Last Answer : (B) 750

Description : __________ is the process of coating the surface of steel with aluminium oxide, thereby imparting it increased resistance to corrosion & oxidation upto a temperature of 700°C. (A) Veneering (B) Galvanising (C) Electroplating (D) Calorising

Last Answer : (D) Calorising

Description : Filter aids like asbestos, kieselguhr, diatomaceous earth etc. are used to increase the porosity of the final filter cake & reducing the cake resistance during filtration. Filter aid is (A) Added to the feed slurry (B) Pre ... the cake by dissolving solids or by burning it off (D) All 'a', 'b' & 'c'

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

Description : Corrosion of metals cannot be prevented by its (A) Tempering (B) Chromising (C) Aluminising (D) Alloying

Last Answer : (A) Tempering

Description : Galvanic corrosion cannot be prevented by (A) Cathodic protection (B) Anodic protection (C) Usage of largest possible anodic area (D) Any one of these

Last Answer : Option B

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.  

Description : For __________ drying, the effects of velocity, temperature and humidity of the gas and the thickness of the solid are the same. (A) Unsaturated surface (B) Constant rate (C) Both (A) and (B) (D) Neither (A) nor (B)

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

Description : The relative saturation of a partially saturated mixture of vapour and gas can be increased by __________ of the mixture. (A) Reducing the total pressure (B) Increasing the total pressure (C) Reducing the temperature (D) Both (B) and (C)

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

Description : If the evaporator temperature of a plant is lowered, keeping the condenser temperature constant, the h.p. of compressorrequired will be (a) same (b) more (c) less (d) more/less depending on rating

Last Answer : Ans: b

Description : If the temperature of intake air in internal combustion engine is lowered, the efficiency will a. increase b. decrease c. remains same d. increases upto certain limit and then decrease

Last Answer : ANSWER a. increase

Description : Which of the following statements concerning the specific gravity of a battery electrolyte is true? A. The electrolyte becomes less dense when it is cooled. B. The specific gravity reading is lowered ... water is added. D. The temperature does not affect the specific gravity of the electrolyte.

Last Answer : Answer: B

Description : The antibacterial action of aminoglycoside antibiotics is characterized by: A. Concentration dependent rate of bacterial cell killing B. Concentration dependent prolonged postantibiotic effect C. More pronounced bactericidal effect in anaerobic medium D. Both 'A' and 'B' are correct

Last Answer : D. Both 'A' and 'B' are correct

Description : In cooling tower ,higher temperature __________ corrosion potential • Decrease • Increase • Temperature has no effect on corrosion

Last Answer : Increase

Description : Pick out the wrong statement: (A) Chemical reactions with high activation energy are very temperature sensitive (B) A flat velocity profile exists in a plug flow reactor (C) The residence ... D) Half life of a reaction increases with increased initial concentration for reaction orders more than one

Last Answer : (C) The residence time for all the elements of fluid in case of a P.F.R. need not be same

Description : Velocity of a reaction depends upon the (A) Nature of the reactants (B) Concentration of the reactants (C) Temperature at which the reaction is carried (D) All (A), (B) and (C)

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

Description : Velocity of a chemical reaction (A) Decreases with increase in temperature (B) Increases with increase of pressure of reactants for all reactions (C) Decreases with increase of reactant concentration (D) None of these

Last Answer : (D) None of these

Description : The cooling effect in a cooling tower can be speeded up by (A) Increasing the air velocity and area of exposed wet surface (B) Reducing the barometric pressure (C) Reducing the humidity of the air (D) All (A), (B) and (C)

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

Description : Pick out the wrong statement. (A) In a batch reactor, which is exclusively used for liquid phase reactions; temperature pressure and composition may vary with time (B) In a semi-batch reactor, ... system (D) In a continuous flow reactor, both the reactants and the products flow out continuously

Last Answer : (C) In a continuous flow reactor, uniform concentration cannot be maintained throughout the vessel even in a well agitated system

Description : Velocity of liquid hydrocarbon fuels in a pipeline cannot be measured by magnetic flow-meters, because their __________ is very low/small. (A) Thermal conductivity (B) Electrical conductivity (C) Specific gravity

Last Answer : (C) Specific gravity

Description : Higher fuel combustion efficiency cannot be achieved by (A) Preheating of fuel gases & combustion air (B) Reducing sulphur content in the fuel (C) Adopting proper fuel firing technique & fuel preparation (D) Supplying correct amount of combustion air

Last Answer : (B) Reducing sulphur content in the fuel

Description : Determine the equivalent weight of the following oxidising and reducing agents : (a) `KMnO_(4)` (reacting in acidic medium `MnO_(4)^(-)rarrMn^(2+)`) (

Last Answer : Determine the equivalent weight of the following oxidising and reducing agents : (a) `KMnO_(4)` (reacting in ... medium `MnO_(4)^(-)rarr MnO_(2)`)

Description : The rate of an enzyme catalyzed reaction was measured using several substrate concentrations that were much lower than Km, the dependence of reaction velocity on substrate concentration can best be ... constant fraction of Vmax (C) Equal to Km (D) Proportional to the substrate concentration

Last Answer : Answer : C

Description : Give Some Methods Of Reducing Stress Concentration?

Last Answer : Some of the methods are: 1. Avoiding sharp corners. 2. Providing fillets. 3. Use of multiple holes instead of single hole 4. Undercutting the shoulder parts.

Description : Finasteride acts by: A. Blocking testosterone receptors in the prostate gland B. Reducing testosterone secretion from testes C. Reducing LH secretion from pituitary D. Lowering circulating as well as prostatic dihydrotestosterone concentration

Last Answer : D. Lowering circulating as well as prostatic dihydrotestosterone concentration

Description : __________ is added in stainless steel to prevent inter crystal corrosion. (A) Vanadium (B) Niobium (C) Chromium (D) Nickel

Last Answer : (B) Niobium

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)

Description : Out of the following processes of paper pulp manufacture, the maximum corrosion problem in digestion & handling equipments is encountered in the __________ process. (A) Mechanical (B) Sulphate/Kraft (C) Sulphite (D) Neutral sulphite semi-chemical

Last Answer : (D) Neutral sulphite semi-chemical

Description : __________ are used as corrosion inhibitor for iron & steel in aqueous solutions. (A) Phosphates (B) Chromates (C) Sulphates (D) Bi-carbonates

Last Answer : (B) Chromates

Description : Notched bar test is used for testing the __________ of a material. (A) Impact strength (B) Endurance limit (C) Machinability (D) Corrosion resistance

Last Answer : (A) Impact strength

Description : Out of the following, the __________ pipe has the least corrosion resistance. (A) Mild steel (B) Copper (C) Cast iron (D) Wrought iron

Last Answer : D) Wrought iron

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

Description : Filtrate flow rate in case of a rotary drum vacuum filter (in which Rm < < Rc ) is proportional to __________ and the cycle time (where, μ = filtrate viscosity Rm = filter medium resistance Rc = cake resistance). (A) √μ (B) 1/√μ (C) 1/μ (D) 1/μ

Last Answer : (B) 1/√μ

Description : The conduction velocity of the nerve fibres is increased by: a. decreased temperature b. increased concentration of the external sodium ions e. increased axon diameter d. myelination

Last Answer : myelination