Which of the following substance is a mixture?
Granulated sugar
Sea-water
Sodium chloride
Iron fillings
Correct answer is B
No explanation has been provided for this answer.
Which of the following compounds is NOT formed by the action of chlorine on methane?
CH3CI
C2H5CI
CH2CI2
CHCI3
Correct answer is B
No explanation has been provided for this answer.
When ethanol is heated with excess concentrated sulphuric acid, the ethanol is?
oxidized to ethene
polymerized to polyethene
dehydrated to ethene
dehydrated to ethyne
Correct answer is C
No explanation has been provided for this answer.
What reaction takes place when palm-oil is added to potash and foam are observed?
Neutralization
Saponification
Esterification
Salting-out
Correct answer is B
The reaction of palm oil with potash is known as saponification reaction, palm oil serves as the organic acid(palmitic acid) while potash( conc. KOH) serves as the base leading to the formation of soap(the presence of bubbles indicate the formation of soap)
Which of the following is used as an 'anti-knock' in automobile engines?
Tetramethyl silane
Lead tetra-ethyl
Glycerol
n-heptane
Correct answer is B
knocking, in an internal-combustion engine, sharp sounds caused by premature combustion of part of the compressed air-fuel mixture in the cylinder.
Knocking is a phenomenon that occurs in a gasoline engine if the fuel used does not have a high enough octane rating.
Anti – knocking agents are chemical compounds added in the fuels that help in effective combustion.
An antiknock agent is a gasoline additive used to reduce engine knocking and increase the fuel's octane rating by raising the temperature and pressure at which auto-ignition occurs.
Examples are:
Ethanol boosts the octane number of fuel, which helps prevent pre-ignition knock.
Organic lead (tetraethyl lead) is used as an antiknock agent in gasoline and jet fuels.