MCQ 131
Which of the following elements is a diatomic molecule?
A) Carbon
B) Oxygen
C) Helium
D) Argon
Answer: B) Oxygen.
Explanation: Diatomic molecules consist of two atoms; oxygen (O₂) is one such example.
MCQ 132
What is the primary role of a solvent in a solution?
A) To change the chemical properties
B) To dissolve the solute
C) To create a solid
D) To increase temperature
Answer: B) To dissolve the solute.
Explanation: The solvent is the substance that dissolves the solute to form a solution.
MCQ 133
What does the term “analyte” refer to in chemistry?
A) The substance being analyzed
B) The solvent in a reaction
C) The catalyst used
D) The resulting product
Answer: A) The substance being analyzed.
Explanation: An analyte is the specific substance whose chemical constituents are being identified and measured.
MCQ 134
Which of the following compounds has the highest melting point?
A) NaCl
B) CO₂
C) H₂O
D) CH₄
Answer: A) NaCl.
Explanation: Sodium chloride (NaCl) has a high melting point due to its strong ionic bonds.
MCQ 135
What type of reaction occurs when two or more substances combine to form a single product?
A) Decomposition
B) Single replacement
C) Synthesis
D) Combustion
Answer: C) Synthesis.
Explanation: A synthesis reaction involves the combination of two or more reactants to produce one product.
MCQ 136
What is the effect of increasing the concentration of reactants in a chemical reaction?
A) Decreases the rate of reaction
B) Has no effect
C) Increases the rate of reaction
D) Makes the reaction exothermic
Answer: C) Increases the rate of reaction.
Explanation: Increasing the concentration of reactants typically increases the rate of reaction due to more frequent collisions.
MCQ 137
What is the primary gas produced during the fermentation of sugars?
A) Oxygen
B) Nitrogen
C) Carbon dioxide
D) Hydrogen
Answer: C) Carbon dioxide.
Explanation: Fermentation of sugars by yeast produces carbon dioxide and alcohol as byproducts.
MCQ 138
Which of the following compounds is considered a strong acid?
A) Acetic acid
B) Citric acid
C) Hydrochloric acid
D) Carbonic acid
Answer: C) Hydrochloric acid.
Explanation: Hydrochloric acid (HCl) is a strong acid that completely dissociates in water.
MCQ 139
What is formed when an acid reacts with a metal?
A) Water and carbon dioxide
B) Salt and hydrogen gas
C) Salt and oxygen gas
D) Water and salt
Answer: B) Salt and hydrogen gas.
Explanation: The reaction between an acid and a metal typically produces a salt and hydrogen gas.
MCQ 140
What does the term “endothermic reaction” refer to?
A) A reaction that releases energy
B) A reaction that absorbs energy
C) A reaction that has no energy change
D) A reaction that occurs spontaneously
Answer: B) A reaction that absorbs energy.
Explanation: An endothermic reaction requires an input of energy, typically in the form of heat.
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