Description : __________ of rubber decreases after its vulcanisation. (A) Resistance to the action of organic solvent (B) Tackiness (C) Maximum service temperature (D) Tensile strength
Last Answer : (B) Tackiness
Description : Vulcanisation of rubber (A) Decreases its tensile strength (B) Increases its ozone & oxygen reactivity (C) Increases its oil & solvent resistance (D) Converts its plasticity into elasticity
Last Answer : (D) Converts its plasticity into elasticity
Description : Vulcanisation of rubber does not increase its (A) Softness (B) Oxidation resistance (C) Weight & strength (D) Elasticity & water solubility
Last Answer : (A) Softness
Description : Pick out the wrong statement. (A) Polymeric fibres are never produced by addition polymerisation (B) Property of tackiness is exhibited by uncured rubber (C) Sharp melting point is not observed in thermoplastic polymers (D) Polythene generally has an excellent resistance to ultra violet rays
Last Answer : (A) Polymeric fibres are never produced by addition polymerisation
Description : Fillers such as zinc oxide and carbon black are added to the crude natural rubber before vulcanisation in order to improve its (A) Elasticity (B) Strength (C) Plasticity (D) Weathering characteristics
Last Answer : (D) Weathering characteristics
Description : Styrene butadiene rubber (SBR) as compared to natural rubber has (A) Poor tensile strength (B) Poorer resistance (C) Greater amount of heat build up heavy loading (D) All (A), (B) and (C)
Last Answer : (D) All (A), (B) and (C)
Description : Styrene-butadiene-rubber (SBR) as compared to natural rubber has (A) Poorer tensile strength (B) Poorer resistance to oxidation (C) Greater amount of heat build-up under heavy loading (D) All (A), (B) and (C)
Description : Neoprene which is used for making shoe heels & belts is superior to natural rubber in its stability to aerial oxidation and resistance to oils & other solvents. The monomer used for making neoprene is (A) Chloroethane (B) Chloroprene (C) Isoprene (D) None of these
Last Answer : (B) Chloroprene
Description : Vulcanisation of rubber does not increase its (A) Elasticity (B) Plasticity (C) Ductility (D) None of these
Last Answer : (B) Plasticity
Description : Peptizers like aromatic mercaptans (e.g. thiophenes) are added in rubber to (A) Protect rubber goods from attack by oxygen & ozone present in the atmosphere (B) Reduce its viscosity to ... processing (C) Reduce the time of vulcanisation and quantity of vulcanising agent (D) Increase its viscosity
Last Answer : (B) Reduce its viscosity to permit easier processing
Description : The process involved in converting rubber into a thin sheet or coating it on fabric is called (A) Extrusion (B) Mastication (C) Calendaring (D) Vulcanisation
Last Answer : (C) Calendaring
Description : Vulcanisation of raw rubber makes it (A) Soft (B) Less elastic (C) Plastic (D) Tacky
Last Answer : (B) Less elastic
Description : Most commonly used rubber vulcanisation agent is (A) Sulphur (B) Bromine (C) Platinum (D) Alumina
Last Answer : (A) Sulphur
Description : Black lung disease occurs in people working in – (1) Electroplating industry (2) Organic solvents industry (3) Paint manufacturing industry (4) Coal mines
Last Answer : (4) Coal mines Explanation: Coal worker's pneumoconiosis, colloquially referred to as black lung disease, is a lung disease that results from breathing in dust from coal, graphite, or man-made carbon ... to be removed by the body; that leads to inflammation, fibrosis, and in worse cases, necrosis.
Description : Black lung disease occurs in people working in (1) Electroplating industry (2) Organic solvents industry (3) Paint manufacturing industry (4) Coal mines
Last Answer : Coal mines
Description : In vulcanisation, with which the natural rubber is heated? -Do You Know?
Last Answer : answer:
Description : In vulcanisation of rubber,
Last Answer : In vulcanisation of rubber, A. sulphur reacts to form new compound B. sulphur cross-links are ... layer over rubber D. all the statements are correct
Description : Which one of the following statements is not correct? Vulcanisation of rubber makes it - (1) soft and flexible (2) strong and hard (3) chemical resistant (4) withstand higher temperatures
Last Answer : (1) soft and flexible Explanation: In order to give more strength and more elasticity, natural rubber is heated with sulphur or sulphur compounds at 150°C temperature. Vulcanized rubber has good ... of vulcanized rubber is enhanced up to 100°C. It has good resistance to organic solvents.
Description : In vulcanisation process, rubber can be hardened by adding - (1) Nitrogen (2) Silicon (3) Sulphur (4) Alcohol
Last Answer : (3) Sulphur Explanation: In order to give more strength and more elasticity, natural rubber is heated with sulphur or sulphur compounds at 150°C temperature. Vulcanized rubber has good tensile strength.
Description : In vulcanisation, with which the natural rubber is heated?
Last Answer : Sulphur
Description : In vulcanisation process, rubber can be hardened by adding (1) Nitrogen (2) Silicon (3) Sulphur (4) Alcohol
Description : Which one of the following statements is not correct? Vulcanisation of rubber makes it (1) soft and flexible (2) strong and hard (3) chemical resistant (4) withstand higher temperatures
Last Answer : soft and flexible
Description : When the steel is subjected to normalising, its __________ decreases. (A) Yield point (B) Ductility (C) Ultimate tensile strength (UTS)
Last Answer : (B) Ductility
Description : Work hardening of a material (A) Decreases its tensile strength (B) Decreases its ductility (C) Increases its ductility (D) Does not affect its ductility
Last Answer : (B) Decreases its ductility
Description : Thermosetting resins/polymers as compared to thermoplastic ones are (A) Soluble in all organic solvents (B) More brittle (C) Formed by addition polymerisation only (D) Easily reshaped & reused
Last Answer : (B) More brittle
Description : What are the three classes of organic solvents?
Last Answer : Typically, organic solvents can be split up in the following classes: Oxygenated, Hydrocarbon, and Halogenated. Oxygenated solvents include alcohols, glycol ethers, ketones, esters, ... solvents include aliphatics and aromatics. Halogenated solvents include those that are chlorinated primarily.
Description : Pick out the wrong statement regarding the solubility characteristics of high polymers. (A) Greater the degree of cross-linking in the polymer, lesser is its solubility (B) Polymers having more ... of the solvent (D) High molecular weight polymers on dissolving gives solution of very low viscosity
Last Answer : (D) High molecular weight polymers on dissolving gives solution of very low viscosity
Description : Addition of plasticisers to polymers results in partial neutralisation of intermolecular forces of attraction between the macro-molecules thereby increasing its (A) Tensile strength (B) Chemical resistance (C) Flexibility (D) All (A), (B) & (C)
Last Answer : (C) Flexibility
Description : Addition of lead, sulphur and phosphorus to low carbon steel helps in improving its (A) Corrosion resistance (B) Tensile strength (C) Machinability (D) Compressive strength
Last Answer : (C) Machinability
Description : Presence of cobalt in steel improves its (A) Cutting ability (B) Corrosion resistance (C) Tensile strength
Last Answer : (A) Cutting ability
Description : Young's modulus of a material is the measure of its (A) Stiffness (B) Malleability (C) Creep resistance (D) Tensile strength
Last Answer : Option A
Description : Can you help me engineer this leak detection system for organic solvents?
Last Answer : answer:I'm sorry that I may not be qualified to answer this question, but these are my ideas. If argon is what will be leaking, you could have some sort of argon detector, and some sort of ... when there are no leaks. Any drop in pressure would signal a leak. Look up pressure decay leak detection.
Description : Assertion(A): Ethyl alcohol is soluble in organic solvents Reason (R): Ethyl alcohol is having non polar ethyl group
Last Answer : Assertion(A): Ethyl alcohol is soluble in organic solvents Reason (R): Ethyl alcohol is having non polar ... is false D. A is false but R is true
Description : Assertion (A): Ethyl alcohol is soluble in organic solvents Reason(R): Calcium chloride can form an addition compound with ethyl alcohol
Last Answer : Assertion (A): Ethyl alcohol is soluble in organic solvents Reason(R): Calcium chloride can form an addition ... is false D. A is false but R is true
Description : Which of the following are capable of denaturing proteins? (a) organic solvents (b) extreme pH (c) heat (d) all of the these
Last Answer : all of the these
Description : Which of the following improperly describes the physical properties of an alkyne? (a) relatively nonpolar (b) nearly insoluble in water (c) less dense than water (d) insoluble in most organic solvents
Last Answer : insoluble in most organic solvents
Description : A nonpolar molecule is usually: w) hydrophilic x) soluble in water y) hydrophytic z) soluble in organic solvents
Last Answer : ANSWER: Z -- SOLUBLE IN ORGANIC SOLVENTS
Description : Elastomers are (A) Thermosetting material (B) Exemplified by protein derivatives (C) Having high flexural strength (D) Having very high tensile strength and heat resistance
Last Answer : (C) Having high flexural strength
Description : Shock resisting steels should possess high (A) Hardness (B) Toughness (C) Tensile strength (D) Wear resistance
Last Answer : (B) Toughness
Description : Plasticisers are added to polymers to improve their (A) Tensile strength (B) Softness & flexibility (C) Acid resistance (D) Alkali resistance
Last Answer : (B) Softness & flexibility
Description : Failure of a material is termed as fatigue failure, if it fails below the yield point. The resistance to fatigue failure of a material is measured by the (A) Ultimate tensile strength (U.T.S.) (B) Endurance limit (C) Elastic limit (D) None of these
Last Answer : (B) Endurance limit
Description : Reduction in the grain size reduces the __________ of the material. (A) Fatigue resistance (B) Tensile strength (C) Creep resistance (D) All (A), (B) & (C)
Last Answer : (C) Creep resistance
Description : Fatigue resistance of a material is measured by the (A) Elastic limit (B) Ultimate tensile strength (C) Young's modulus (D) Endurance limit
Last Answer : (D) Endurance limit
Last Answer : (D) All (A), (B) & (C)
Description : Pick out the wrong statement. (A) The toughness of a material decreases, when it is heated (B) Crane hooks are normally made of wrought iron (C) Cold working of a metal decreases its ... (D) The temperature at which new grains are formed in a metal is known as the recrystallisation temperature
Last Answer : (C) Cold working of a metal decreases its fatigue strength
Description : Normalising does not __________ of a metal. (A) Improve machinability & tensile strength (B) Remove internal stresses (C) Refine the structure (D) Remove strains caused by cold working
Last Answer : Option B
Description : The resistance to fatigue of a material is measured by (a) elastic limit (b) Young's modulus (c) ultimate tensile strength (d) endurance limit
Last Answer : (d) endurance limit
Description : Weld decay will cause which of the following problems? a) A reduced resistance to corrosion b) a lower tensile strength c) The toughness is reduced d) The hardness will increase
Last Answer : a) A reduced resistance to corrosion