MCQ Collection
MDCAT Chemistry MCQs
Practice MDCAT Chemistry questions with answers and explanations.
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Correct Answer: B. 0.40 M
Explanation:
Moles NaOH=0.0200×0.50=0.0100 mol.
The HCl concentration is 0.0100/0.0250=0.40 M.
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Correct Answer: D. Loss of electrons or increase in oxidation number
Explanation:
Oxidation and reduction occur together.
The oxidized species donates electrons.
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Correct Answer: A. Gain of electrons or decrease in oxidation number
Explanation:
A reduced species accepts electrons.
Reduction accompanies oxidation.
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Correct Answer: B. A species that causes oxidation and is itself reduced
Explanation:
The oxidizing agent accepts electrons.
Its oxidation number decreases.
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Correct Answer: C. A species that causes reduction and is itself oxidized
Explanation:
The reducing agent donates electrons.
Its oxidation number increases.
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Correct Answer: D. An electrochemical cell producing electrical energy from a spontaneous reaction
Explanation:
A galvanic or voltaic cell converts chemical energy into electrical energy.
Electrons flow through an external circuit.
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Correct Answer: A. A cell using electrical energy to drive a nonspontaneous reaction
Explanation:
Electrolysis requires an external power source.
It can produce metals, gases, or chemical changes.
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Correct Answer: B. At the anode
Explanation:
The mnemonic 'An Ox' identifies oxidation at the anode.
Electrons are produced there.
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Correct Answer: C. At the cathode
Explanation:
The mnemonic 'Red Cat' identifies reduction at the cathode.
Electrons are consumed there.
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Correct Answer: D. Change in concentration of reactant or product per unit time
Explanation:
Reaction rate measures how fast composition changes.
It may be expressed using disappearance or formation rates.
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Correct Answer: D. Maintain electrical neutrality by ion migration
Explanation:
The salt bridge completes the internal ionic circuit.
It prevents rapid charge buildup in half-cells.
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Correct Answer: A. Dependence of reaction rate on reactant concentrations
Explanation:
A rate law is determined experimentally.
Its exponents define reaction orders.
