This set of Applied Chemistry Questions and Answers for Experienced people focuses on “Viscosity and Viscosity Index – 2”.
1. Redwood viscometer no1 is used to find the viscosity of the _________ liquids.
a) High viscous
b) Low viscous
c) Moderate viscous
d) No viscous
View Answer
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.
2. What is the efflux of the redwood viscometer no2?
a) 2000
b) 20000
c) 100
d) 200
View Answer
Explanation: The efflux of the redwood viscometer no2 is 200 seconds or less. Its jet for the outflow of the oil is having larger diameter. We can find the relative viscosities of the liquids using the redwood viscometer.
3. Test thermometer is one of the parts of the redwood viscometer.
a) True
b) False
View Answer
Explanation: The parts of the redwood viscometer are test thermometer, bath thermometer, water inlet, oil stirrer, water bath, heating coil, metal indicator, brass oil cup, water bath stirrer blade, valve rod, water outlet, agate jet, kohlrausch flask and levelling screw.
4. The oil cup is made up of _________
a) Brass
b) Copper
c) Silver
d) Chromium
View Answer
Explanation: The oil cup is one of the parts of the redwood viscometer. It is made up of brass. It is open at upper end. Its base is fitted with an agate jet, with the bore of diameter 1.62mm and internal length 10mm.
5. The height and diameter of the oil cup is __________ respectively.
a) 250mm, 46.5mm
b) 290mm, 46.5mm
c) 290mm, 40.5mm
d) 250mm, 40.5mm
View Answer
Explanation: The height of the oil cup is 290mm and the diameter is about 46.5mm. The level to which the oil cup is fixed with oil is indicated by the stout wire fixed in the side of the oil cup. The wire is turned upwards and it is tapered to sharp point to indicate level properly.
6. The jet is opened or closed by ___________
a) Cup
b) Valve rod
c) Stout wire
d) Screw
View Answer
Explanation: The jet of the redwood viscometer is opened or close by using the valve rod. The lid of the cup is provided with the spirit level for the vertical levelling of the jet.
7. The cylindrical vessel will be around the oil cup which serves as a water bath made up of __________
a) Brass
b) Chromium
c) Copper
d) Aluminium
View Answer
Explanation: The oil cup is surrounded by a cylindrical vessel and it acts as a water bath that is made up of the copper. It is provided by a tap. The tap is used for emptying the vessel by draining the water present in it.
8. The long side tube is used to heat the water by means of ________
a) Burner
b) Spirit lamp
c) Bunsen burner
d) Candle
View Answer
Explanation: The long side tube is projected outwards. This is used to heat the water by means of gas or spirit lamp. The copper vessel is provided with thermometer to measure the temperature of the water.
9. The water bath is provided with stirrer having ________ blades.
a) One
b) Two
c) Three
d) Four
View Answer
Explanation: The water bath is provided with a stirrer having four blades. It is provided with four blades because it helps to maintain the uniform temperature in bath to facilitate the uniform heating of the oil.
10. The entire redwood viscometer apparatus rests on _________
a) Table
b) Stand
c) Tripod stand
d) Burner
View Answer
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.
11. The capacity of the flask is about ___________
a) 100ml
b) 150ml
c) 50ml
d) 25ml
View Answer
Explanation: 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.
12. The absolute viscosity of the oil can be given as _____________
a) ŋ = k{(t1D2)/(t2D1)}
b) ŋ = k{(t1D2)+(t2D1)}
c) ŋ = k{(t1D2)(t2D1)}
d) ŋ = k{(t1D2)-(t2D1)}
View Answer
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.
13. The value of the arbitrary constant K is _________ for water.
a) 1
b) 100
c) 2
d) 50
View Answer
Explanation: 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.
14. The kinematic viscosity of the oil can be calculated by ___________
a) V = ŋ+ρ
b) V = ŋ/ρ
c) V = ŋ – ρ
d) V = ŋ*ρ
View Answer
Explanation: The kinematic viscosity means the viscosity that determines the kinematic energy of the liquid that means it determines the speed of the oil. So, the kinematic viscosity of the oil is given by V=ŋ/ρ, where ŋ = absolute viscosity of the oil and ρ = density of the oil.
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