Learn more about the properties, composition, and structure of substances (elements and compounds) with these Chemistry questions and answers. This Test can be used by students preparing for Chemistry in JAMB, WAEC, NECO or Post UTME.
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.
Which of the following is NOT correct test for the named organic compound in each case?
Butanoic acid solution gives effervescence with Na2CO3 solution
Glucose when reacted with Na2CrO4 at 0°C will show immediate discharge of colour
When but-2-ene is reacted with dilute solution of KMnO4 the purple colour of KMnO is discharged readily even room temperature
When butan-2-ol is boiled with butanoic acid with a drop of concentrated H2SO4 a sweet smelling liquid is produced
Correct answer is B
No explanation has been provided for this answer.
Electrolysis of solution of its salts
Decomposition of its oxides
Displacement from solution by an alkali metal
Electroiysis of fused salt
Correct answer is D
No explanation has been provided for this answer.
KCI
NaNO3
K2SO4
CaSO4
Correct answer is C
No explanation has been provided for this answer.
lead (II) oxide
calcium oxide
zinc oxide
lead nitrate
Correct answer is C
No explanation has been provided for this answer.