This set of Applied Chemistry Multiple Choice Questions & Answers (MCQs) focuses on “Neutralization/Acidic Number”.
1. Acid number of a lubricating oil is _________ required to neutralise all acidic constituents of 1 g of oil.
a) Mgs of KOH
b) Mgs of K2SO4
c) Mgs of NaOH
d) Mgs of Na2SO4
View Answer
Explanation: Acid number of lubricating oil is defined as the mgs of KOH required to neutralise the all acidic constituents of 1g of oil. So, it is also called as the neutralisation number.
2. The fatty oils mostly constitute _________
a) Glycerine
b) Glycol
c) Ethanol
d) Glycerol
View Answer
Explanation: The fatty acids constitute most of the part with glycerol. It also has the esters of higher fatty acids as the next major constituents. In some cases, we can also observe that a notable amount of free acids are also present in fatty acids.
3. The acid content ______ with time.
a) Decreases
b) Increases
c) Remains constant
d) Becomes zero
View Answer
Explanation: The acid content will be increasing with time because as the time goes on the chemical reaction takes place and the number of H+ ions increases with increase in time. So, the acid content also increases with time.
4. Periodic determination of acid number is useful to indicate the progress of ________
a) Oxidation number
b) Reduction number
c) Acidic number
d) Neutralisation number
View Answer
Explanation: The periodic determination of the acid number is useful to indicate the progress of oxidation number. The age of the oil is determined by the increase in acid number with time due to hydrolysis with moisture.
5. The acid value of the lubricating oil is must be less than _______
a) 7
b) 0.7
c) 1
d) 0.1
View Answer
Explanation: The acid value of the lubricating oils must be always less than that of the 0.1. It is because the acid value changes the progress of the oxidation number and hydrolysis rate and moisture content. Based on which we have to replace the lubricating oil.
6. The unblended petroleum oils must have ______ neutralisation values.
a) Very high
b) Very low
c) Negligible
d) Zero
View Answer
Explanation: The neutralisation values of the unblended petroleum oils will be very low. The neutralisation values of the unblended petroleum oils ranges from 0.02 to 0.1. Values higher than this indicate faulty refining.
7. Compounded oils have higher neutralisation values.
a) True
b) False
View Answer
Explanation: The Compounded oils are also called as blended oils. The unblended oils have very less neutralisation number. It is about 0.02 to 0.1. The blended or compounded oils have very high neutralisation number.
8. The higher values of blended oils is because of the presence of ___________
a) Catalyst
b) Salts
c) Additives
d) Reagents
View Answer
Explanation: The high values of neutralisation of blended oils are because of the presence of the additives. The additives present in the oiliness carriers, oxidation and corrosion inhibitors, etc.
9. The neutralisation number is increased due to _________
a) Pureness
b) Contamination
c) Hydrolysis
d) Catalysis
View Answer
Explanation: The neutralisation number is increased due to the contamination as the oil is used. Examples are sulphur dioxide on combustion of sulphur, carbondioxide on combustion of carbon or present in the atmosphere.
10. Darkening of the oil colour takes place due to ________
a) Oxidation
b) Reduction
c) Hydrolysis
d) Catalysis
View Answer
Explanation: The darkening of the oil colour is due to the oxidation. On oxidation the formation of all soluble alcohols, ketones, acids and peroxides are produced. There by increasing the acid number, viscosity and darkening of the oil colour.
11. The neutralisation number cannot give the __________ of the lubricating oil.
a) Corrosive nature
b) Amount of acid
c) Amount of base
d) Moisture level
View Answer
Explanation: The neutralisation number gives about the amount of acid present in lubricating oil, amount of base present in the lubricating oil, amount of moisture present in the lubricating oil. It cannot give about of the source of the oil and the corrosive nature of the oil.
12. The total acid number of an oil is given by __________
a) Acid value = (volume of 0.1N KOH taken*56)/(weight of oil used)
b) Acid value = (volume of 0.01N KOH used*56)/(weight of oil taken)
c) Acid value = (volume of 0.1N KOH used*56)/(weight of oil taken)
d) Acid value = (volume of 0.01N KOH taken*56)/(weight of oil used)
View Answer
Explanation: The total acid number of an oil is given by Acid value= (volume of 0.1N KOH used*56)/(weight of oil taken), where the 0.1 is the maximum value of the oil and 56 is the molecular weight of the KOH.
13. The corrosion problems are caused by _________ in lubricating oil.
a) Potassium chloride
b) Naphthenic acid
c) Sodium chloride
d) Carbon dioxide
View Answer
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.
14. The other parameters apart from the acid number can also determine by the process _______
a) Potentiometer titration
b) Colour indicating titration
c) Spectroscopic methods
d) Catalysis
View Answer
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.
15. In potentiometric titration, the sample is dissolved in _____ and ______
a) Toulene, propanol
b) Toulene and phenolphthalein
c) Toulene and phenol
d) Toulene and benzene
View Answer
Explanation: In potentiometric titration, the sample is generally dissolved in the toulene and propanol with little water and then titrated with the alcoholic potassium hydroxide. A glass electrode and reference electrode is immersed in the sample.
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