1. Darkening of the oil colour takes place due to ________
a) Oxidation
b) Reduction
c) Hydrolysis
d) Catalysis
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.
2. The neutralisation number cannot give the __________ of the lubricating oil.
a) Corrosive nature
b) Amount of acid
c) Amount of base
d) Moisture level
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.
3. 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)
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.
4. The corrosion problems are caused by _________ in lubricating oil.
a) Potassium chloride
b) Naphthenic acid
c) Sodium chloride
d) Carbon dioxide
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.
5. 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
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.
6. In potentiometric titration, the sample is dissolved in _____ and ______
a) Toulene, propanol
b) Toulene and phenolphthalein
c) Toulene and phenol
d) Toulene and benzene
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.
7. Saponification is the value of oil for which the number of mgs of KOH required to saponify the ________ present in the 1g of oil.
a) Fatty materials
b) Salts
c) Free acids
d) Bases
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.
8. It is __________ of fatty oils which leads to formation of soaps.
a) Alkaline hydrolysis
b) Alkaline electrolysis
c) Hydrolysis
d) Electrolysis
Explanation: It is alkaline hydrolysis of fatty oils which leads to formation of soaps. As the fatty materials are present in the oil, that oil on saponification that means on alkaline hydrolysis gives the soaps as product.
9. Which of the following is not saponifiable?
a) Ground nut oils
b) Mineral oils
c) Castor oil
d) Coconut oil
Explanation: The castor oil, coconut oil and the ground nut oil are saponifiable. The mineral oils are not saponifiable. They are mixtures of hydrocarbons and do not react with KOH. So, they are not saponifiable.
10. ________ get large amount of alkali to hydrolysis.
a) Baby oil
b) Liquid paraffin
c) Vegetable oil
d) Liquid petroleum
Explanation: The vegetable oils and animal oils need large amount of alkali to hydrolysis. They are the mixture of glyceryl and esters of fatty acids. Baby oil, liquid paraffin and liquid petroleum are the mineral oils and they are not saponifiable.