Description : Setting of plaster of paris involves – (1) dehydration process (2) hydration to form other hydrates (3) oxidation process (4) reduction process
Last Answer : (2) hydration to form other hydrates Explanation: The setting of plaster of Paris takes place by hydration due to the formation of a solid crystalline hydrate and hardening of Plaster of Paris is ... . A slight expansion takes place in the process and heat is evolved. This process is exothermic.
Description : Setting of plaster of paris involves (1) dehydration process (2) hydration to form other hydrates (3) oxidation process (4) reduction process
Last Answer : hydration to form other hydrates
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 : . Plasticisers are added to paints to (A) Make it corrosion resistant (B) Make glossy surface (C) Give elasticity & prevent cracking of the film (D) Increase atmospheric oxidation
Last Answer : (C) Give elasticity & prevent cracking of the film
Description : Setting of plaster of Paris is accompanied with (A) Hydration (B) Dehydration (C) Hydrolysis (D) Loss of CO2
Last Answer : (A) Hydration
Description : __________ of quicklime produces slaked lime. (A) Hydration (B) Dehydration (C) Hydrogenation (D) None of these
Description : The reduction of the PH value, by the action of atmospheric carbon dioxide with the alkali of the cement paste is called [ A ] atmospheric corrosion [ B ] chloride corrosion [ C ] oxidation [ D ] carbonation
Last Answer : [ D ] carbonation
Description : The remains of salt over the soil after evaporation of water is known as a. water logging b. salivation c. dehydration d. hydration
Last Answer : d. hydration
Description : The process by which an amino acid loses its amino group is called: a) hydration b) deamination c) oxidoamination d) dehydration
Last Answer : ANSWER: B -- DEAMINATION
Description : Cement is made hard with (1) dehydration (2) hydration and dissociation of water (3) Dissociation of water (4) Polymerisation
Last Answer : hydration and dissociation of water
Description : The bright glow of a combustion process is the characteristic of __________ temperature oxidation of coal. (A) Fast & high (B) Slow & low (C) Slow & high (D) Fast & slow
Last Answer : (A) Fast & high
Description : Concentration of hydrogen peroxide is done by (A) Crystallisation (B) Vacuum crystallisation (C) Atmospheric distillation (D) Dehydration
Last Answer : (B) Vacuum crystallisation
Description : Cement setting under water employs a/an __________ process. (A) Hydration (B) Decomposition (C) Oxidation (D) Reduction
Description : Gobar gas is produced by the __________ of 'gobar' (cow dung). (A) Hydrolysis (B) Fermentation (C) Oxidation (D) Dehydration
Last Answer : (B) Fermentation
Description : Which of the following processes is involved in the biochemical treatment of sewage effluents? (A) Oxidation (B) Reduction (C) Dehydration (D) Fermentation
Last Answer : (A) Oxidation
Description : Styrene is produced from ethyl benzene by the process of (A) Dehydrogenation (B) Oxidation (C) Alkylation (D) Dehydration
Last Answer : (A) Dehydrogenation
Description : The biochemical treatment applied to sewage effluents is a process of (A) Dehydration (B) Reduction (C) Oxidation (D) Polymerisation
Last Answer : (C) Oxidation
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
Description : How does the of Hydration Enthalpy of alkaline earth metals vary & compare it with alkali metals
Last Answer : Ans The hydration enthalpies of alkaline earth metal ions decrease with increase in ionic size down the group. Be2+> Mg2+ > Ca2+ > Sr2+ > Ba2+ The hydration enthalpies of alkaline earth metal ions ... MgCl2 and CaCl2 exist as MgCl2.6H2O and CaCl2· 6H2O while NaCl and KCl do not form such hydrates.
Last Answer : The hydration enthalpies of alkaline earth metal ions decrease with increase in ionic size down the group. Be2+> Mg2+ > Ca2+ > Sr2+ > Ba2+ The hydration enthalpies of alkaline earth metal ... and CaCl2 exist as MgCl2.6H2O and CaCl2· 6H2O while NaCl and KCl do not form such hydrates.
Description : When water itself combines chemically with some element or mineral it is called – (1) Carbonation (2) Desilication (3) Hydration (4) Oxidation
Last Answer : (3) Hydration Explanation: When water combines chemically with other elements, the process is called hydration. In organic chemistry, a hydration reaction is a chemical reaction in which a hydroxyl ... runs in a strong acidic, aqueous solution. Hydration leaves the non-water component intact.
Description : Chemical weathering of soil is caused due to (A) Oxidation (B) Carbonation (C) Hydration (D) All the above
Last Answer : Answer: Option D
Description : When water itself combines chemically with some element or mineral it is called (1) Carbonation (2) Desilication (3) Hydration (4) Oxidation
Last Answer : Hydration
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 : Which of the following is the most prone to atmospheric corrosion? (A) Silver (B) Iron (C) Tin (D) Copper
Last Answer : (B) Iron
Description : Higher concentration of nitrogen dioxide in atmospheric air causes (A) Cancer (B) Bronchitis (C) Asphyxiation (D) Corrosion
Last Answer : (B) Bronchitis
Description : Ceramic nuclear metals compared to solid nuclear metals have (A) Higher melting points (B) Low strength at high temperature (C) More chances of radiation damage (D) Poorer corrosion resistance
Last Answer : (A) Higher melting points
Description : The metals occuring at the lower most position in the electromotive series (A) Do not resist corrosion (B) Resist corrosion very strongly (C) Are very brittle (D) Are heat insulators
Last Answer : (B) Resist corrosion very strongly
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
Description : Exposure to SO2 containing chimney gases results in the (A) Reduction in strength of leather & cloth (B) Acceleration of corrosion rates of metals (C) Increased drying & hardening time of paints (D) All (A), (B) and (C)
Description : Sacrificial anode method is used in the protection of pipelines which are buried underground. Sacrificial anode (A) Occurs higher in the electro-chemical series of metals (B) Is exemplified by magnesium plate (C) ... cathodic base material to be guarded against corrosion (D) All (A), (B) & (C)
Last Answer : (D) All (A), (B) & (C)
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
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
Description : Corrosion of metals cannot be prevented by its (A) Tempering (B) Chromising (C) Aluminising (D) Alloying
Last Answer : (A) Tempering
Description : How can wet carbon dioxide be responsible for a corrosion problem in iron-containing metals?
Last Answer : Carbon dioxide reacts with water according to the following equation: CO2 + H2O -> HCO3- + H+ As the concentration of CO2 increases, so does the concentration of the H+ ion. This ion ... ions produced can react with the bicarbonate ions to form ferrous carbonate, which precipitates as a scale.
Description : The process of elimination of water from any system is called (a) Oxidation (b) Reduction (c) Dehydration (d) Evaporation
Last Answer : Ans:(c)
Description : Sulphur dioxide bleaches colouring matter by – (1) Reduction (2) Dehydration (3) Decomposition (4) Oxidation
Last Answer : (1) Reduction Explanation: Sulphur dioxide gas exhibits bleaching properties in presence of moisture. It dissolves in water liberating nascent hydrogen. Nascent hydrogen removes oxygen atoms from the colouring matter (reduces colouring matter) and it loses its colour.
Description : The action of concentrated sulfuric acid on sugar best described as: w) catalysis x) oxidation y) reduction z) dehydration
Last Answer : ANSWER: Z -- DEHYDRATION
Description : Sulphur dioxide bleaches colouring matter by : (1) Reduction (2) Dehydration (3) Decomposition (4) Oxidation
Last Answer : Reduction
Description : Aluminium alloy is one of the most suitable materials of construction for aircrafts mainly due to its (A) High strength to weight ratio (B) Low temperature strength properties (C) Its ability ... rolled, forged & stamped (D) High strength and corrosion & oxidation-resistance at elevated temperature
Last Answer : (A) High strength to weight ratio
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 : Tricalcium aluminate (C3A) (A) Reacts fast with water (B) Generates less heat of hydration (C) Causes initial setting and early strength of cement (D) Does not contribute to develop ultimate strength
Last Answer : Answer: Option B
Description : Define Atmospheric corrosion. State the factors affecting rate of atmospheric corrosion.
Last Answer : Atmospheric corrosion: This type of corrosion occurs when metal surface comes in immediate contact directly with atmospheric gases like O2, Cl2, Br2, I2, H2S, CO2, SO2, NO2 etc. Factors affecting rate of atmospheric corrosion:- 1) Impurities in the atmosphere. 2) Moisture in the atmosphere.
Description : Define atmospheric corrosion. Write mechanism of atmospheric corrosion with diagram.
Last Answer : Atmospheric corrosion: This type of corrosion occurs when metal surface comes in immediate contact directly with atmospheric gases like O2, Cl2, Br2, I2, H2S, CO2, SO2, NO2 etc.
Description : A 47-year-old patient undergoing a complicated laparotomy for bowel obstruction develops a postoperative enterocutaneous fistula. Which of the following statement(s) is/are true concerning parenteral ... use of TPN better prepares the patient for surgery if surgical intervention proves necessary
Last Answer : Answer: a, b, d Patients with gastrointestinal-cutaneous fistulas represent the classical indication for TPN. In such patients, oral intake of food almost invariably results in increased ... treated more aggressively surgically after a defined period of nutritional support (unless closure occurs)
Description : Which metals are very corrosion resistant?
Last Answer : Bronze.
Description : Write about the corrosion of metals by water, steam and soil in detail.
Last Answer : Corrosion (i)by water: physical configuration of the system hardness of water, salts, chlorides, and dissolved gases such as oxygen, carbon dioxide, and sulphur dioxide. Presence of suspended ... is more corrosion is less. If dissolved salts more, conductivity is more and corrosion is more.
Description : Which one of the following metals is immune to corrosion by air, water, hydrochloric acid and nitric acid; but is soluble in aqua regia? w) gold x) silver y) magnesium z) nickel
Last Answer : ANSWER: W -- GOLD