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Correct option is (a) Weak

To explain I WOULD say: The fatty ACIDS have low INTERMOLECULAR forces as they are FORMED from glyceryl. They are responsible for the lowering of the melting point of soaps.

Right option is (a) 1

To explain: The absolute viscosity of the oil after performing the EXPERIMENT in REDWOOD viscometer can be GIVEN by ŋ=k{(t1D2)/(t2D1)}. Here k is called as the arbitrary constant. The value of the arbitrary constant for WATER is 1. The value of the arbitrary constant for rape SEED oil is 100.

The correct choice is (d) Zero V.I

Explanation: The VISCOSITY of some lubricating oils CHANGES by the change in the temperature very RAPIDLY. For such oils the V.I will be zero and for the viscosity of the oils which changes slightly with the change in temperature will have V.I high.

Correct choice is (C) Copper CORROSION

For explanation: The tiadiazole and triazole DERIVATIVES are used to protect the NON ferrous metals from corrosion. They also protect the copper derivatives from corrosion. Organic phosphates and SODIUM and sodium and calcium sulphonates are used as the rust inhibitors in machinery.

The CORRECT CHOICE is (a) coefficient of FRICTION

To elaborate: The coefficient of friction will be low for the solid lubricants and it is ONE of the disadvantages of the solid lubricants. They are stable at HIGH temperatures also. Cleanliness of the solid lubricants is also high.

The CORRECT option is (b) 15µm

Explanation: The thickness of the MoS2 film is about 15µm. This is the lubricant having lamellar structure with LOW shear STRENGTH and effective in lubrication. It forms a very THIN layer on SURFACES.

The CORRECT option is (a) 1^oC

The explanation is: The cloudiness of the lubricant is OBSERVED for every 1^oC. First the oil is taken into the JAR up to the marked level. The cork is fitted and then HEATED and observed for cloudiness for every 1^oC RAISE in temperature.

Correct OPTION is (B) (C/F)*100

Best explanation: The percentage of fatty oil when COMPOUNDED in the oil is given by (C/F)*100. Here, C = saponification value of the compounded or lubricating oil and F = saponification of the fatty oil.

The correct option is (c) 50ml

To explain: The capacity of the flask is about 50ml. It has SPECIFIC shape. Is receives the oil from the jet outlet. This flask is KNOWN as kohlrasch flask.The whole PROCESS takes place in the flask.

The CORRECT choice is (a) Itself

For explanation I would say: The viscosity of the LIQUID is defined as the resistance offered by the liquid for its own flow. The viscosity is more for the FLUIDS having more DENSITY. The flow of one layer of the liquid is actually opposed by the other layer of the same liquid.

Right choice is (a) True

The best I can EXPLAIN: The continuous fluid film cannot be MAINTAINED between the rubbing surfaces under the CONDITION such as high load, slow rate of rotation and very low viscosity OIL, etc. These conditions are seen in boundary lubrication.

Right option is (d) detergents

The explanation: The OIL insoluble sludge can be reduced by using detergents. DESPERSANTS are SIMILAR to detergents. VANISH and carbon from fuel combustion in internal combustion engines, there will be depositions of oil insoluble materials. Those are reduced by detergents.

Correct choice is (a) Friction modifiers

To elaborate: The friction modifiers are used in the auto mobile applications. MILD extreme PRESSURE AGENT in boundary lubrication conditions are, they prevent stick SLIP oscillations and control noise in the automatic TRANSMISSIONS.

The correct choice is (C) 4

The EXPLANATION is: There are four types of lubricants ACCORDING to the classification on the basis of the SHEAR strength. They are solid, LIQUID, semi-solid and gaseous lubricants. Shear strength is the strength against the structural failure of the component.

The correct CHOICE is (a) Brass

To explain: Oil CUP in Pensky-marten’s apparatus is MADE with the brass. Brass does not undergo rusting. The oil cup is made with metals that do not undergo rusting. Iron, copper and STEEL undergo rusting and having EQUIVALENT conductivity.

The correct option is (a) Fatty materials

Explanation: The saponification is the VALUE of oil determined as the number of mgs of KOH needed to saponify the fatty materials present in the 1g of oil. If it is FREE acids INSTEAD of fatty materials then it is called as neutralisation number.

The correct CHOICE is (c) COOLING mixture

Explanation: Cooling BATH contains SUITABLE cooling mixture. It may be water sometimes but it is selected according to the lubricant. It is mainly used for cooling purposes.

The correct OPTION is (c) Spectroscopic methods

Easiest explanation: The other parameters apart from the acid NUMBER ALSO given by the spectroscopic methods. The potentiometer titration and colour indicating titrations are USED to deduce only the acid number.

Right answer is (b) Emulsions

The explanation: A dispersion system CONSISTING of TWO immiscible LIQUIDS is called emulsions. A substance is added to the emulsions called emulsifying agents for stabilization. The emulsifying agents SHOW polar or non polar natures accordingly.

Right answer is (b) hexagonal RINGS

Easiest EXPLANATION: The crystal lattice structure of the inorganic lubricants has hexagonal rings forming THIN PARALLEL planes. WITHIN the plane each atom is strongly bonded with covalent bonds. Each plane is bonded by weak vaanderwal forces.

The correct ANSWER is (c) Be destroyed

To explain I WOULD say: As the MELTING point INCREASES, the atomic bonds will be destroyed. It makes the LUBRICATION less effective.

Right option is (d) 5-40^oC

Easy EXPLANATION: The fire is POINT of an OIL is usually greater than the FLASH point of it. The fire point of oil is about 5-40^oC higher than the flash point.

The correct choice is (C) Good dielectric strength

For explanation: The TRANSFORMER oils must be filtered and dried properly before they PUT into use because any moisture in them may DAMAGE the device or leads to short CIRCUITS. The dielectric oils must have good dielectric strength.

Correct ANSWER is (a) 0.2-8.0

Easiest EXPLANATION: The acid value of the groundnut oil is 0.2-8.0. CASTOR oil has the acid value of 0.4-0.8. Coconut oil is having a HIGH acid value that is about 10.0-35.2.

Correct option is (d) NaOH

To explain I WOULD say: The HARD soaps are formed by using the sodium hydroxide. The potassium hydroxide is used to produce soft soaps. Hard soaps can give the lather EVEN with hard WATER.

The correct ANSWER is (b) NAPHTHENIC ACID

Explanation: The corrosion problems are due to the presence of the naphthenic acid that is why the acid number alone cannot give about the corrosion NATURE as it cannot give about the amount of naphthenic acid present.

Right OPTION is (a) ŋ = k{(t1D2)/(t2D1)}

Explanation: By PERFORMING the redwood VISCOMETER experiment, we can know the absolute viscosity of the oils. The absolute viscosity of the oils can be given by ŋ=k{(t1D2)/(t2D1)} where, t1=time in SECONDS, taken for the flow of the 50 c.c of oil, t2=time in seconds, taken for the flow of 50 c.c standard oil or LIQUID. D1=specific gravity of the oil to be tested. D2=specific gravity of the standard liquid. K = arbitrary constant.

Correct choice is (c) TRIPOD stand

Best explanation: The entire redwood VISCOMETER apparatus rests on the tripod stand. It is provided with screws at the bottom. It has four legs. The screws are used for ADJUSTING the legs for INCREASING or decreasing the diameter.

The correct option is (b) High BOILING point

The best I can explain: A good liquid lubricant must possess the PROPERTIES LIKE adequate viscosity, high boiling point, low freezing point, good oiliness. It also CONTAINS stability towards the oxidation and heat.

Correct option is (d) 150MM

Easiest explanation: The TEST tube is having the length of 150mm. It has a DIAMETER of 25mm. The stirrer is attached for even miscibility of aniline and the LUBRICATING oil.

The correct OPTION is (b) Low viscous

Explanation: The redwood viscometer no1 is used to FIND out the viscosity of the low viscous liquids. They have an EFFLUX of 2000seconds or LESS. Redwood viscometer no2 is used to find the viscosity of the high viscous liquids LIKE fuel oils.

Correct OPTION is (C) Increases

The explanation: The viscosity of an oil decreases with an increase of the temperature. In internal combustion ENGINES and aeroplanes, the engine must start at LOW temperature and as well they must be operated at high TEMPERATURES. So, the viscosity of an oil must be moderate.

Right ANSWER is (b) True

Best EXPLANATION: The friction modifiers have 12 to 18 CARBONS. The fatty ALCOHOLS and esters of fatty acids also act as friction modifiers. Glyceride of the rapeseed and lard oil is used as the friction modifiers in machineries.

Correct choice is (a) 3-20%

The BEST explanation: Oil in water emulsion is obtained by adding the oil to a SUFFICIENT AMOUNT water that is about 3 to 20%. The emulsifying agents must be water soluble like SODIUM soaps or sodium or potassium SALTS or sulphides.

The correct option is (b) cup GREASES

To explain I would say: Cup greases are produced by mixing the slaked lime solution with the TALLOW oil with constant stirring at hot condition. After soap formation is COMPLETE petroleum is added to it and mixed. Some AMOUNT of water is generally mixed with greases.