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 organic compound is responsible for the characteristic aroma of fruits?
Alkane
Alkyne
Ester
Amine
Correct answer is C
Esters are organic compounds that have a pleasant, fruity aroma. They are responsible for the characteristic smells of fruits and many other fragrant substances.
Which of the following factors does NOT affect the rate of a chemical reaction?
Concentration of reactants
Presence of a catalyst
Molecular weight of products
Temperature
Correct answer is C
The molecular weight of products is not directly related to the rate of a chemical reaction. The factors that affect the reaction rate include concentration of reactants, temperature, presence of catalysts, surface area, and the nature of the reactants and products.
When an acidic solution is diluted, what happens to its pH?
It depends on the specific acid
It decreases
It remains the same
It increases
Correct answer is D
When an acidic solution is diluted by adding more solvent (usually water), the concentration of hydrogen ions (H\(^+\)) decreases. As a result, the pH of the solution increases, making it less acidic
What is the product of the electrolysis of aqueous sodium chloride (NaCl) using inert electrodes?
Hydrogen gas at the cathode and chlorine gas at the anode
Hydrogen gas at the cathode and oxygen gas at the anode
Sodium metal at the cathode and chlorine gas at the anode
Sodium metal at the cathode and oxygen gas at the anode
Correct answer is B
During the electrolysis of aqueous sodium chloride using inert electrodes (such as platinum or carbon), the cations (H\(^+\)) are attracted to the cathode and are reduced to form hydrogen gas (H\(_2\)). The anions (OH\(^-\)) are attracted to the anode and are oxidized to form oxygen gas (O\(_2\)).
Which of the following alkanes has a straight-chain structure?
Cyclopentane (C5H10)
Isobutane (C4H10)
2 - methyl propane (C4H10)
Pentane (C5H12)
Correct answer is D
Pentane (C5H12) is a straight-chain alkane. Alkanes are hydrocarbons with the general formula CnH2n+2. They are called straight-chain alkanes if all the carbon atoms are connected in a continuous chain without any branches. Butane and Isobutane are both C4H10, but Isobutane has a branched structure, not a straight chain. Cyclopentane (C5H10) is a cycloalkane, not a straight-chain alkane.