Chemistry MDCAT MCQs

Organic, inorganic & physical chemistry MCQs

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Showing 305 MCQs in Chemistry
Chemistry
A. H2SO4
B. H2S
C. SO2
D. SCl2
Answer: Sulfuric acid (H2SO4) is an oxoacid because it contains oxygen, hydrogen, and sulfur.
Chemistry
A. Acetic acid
B. Hydrochloric acid
C. Carbonic acid
D. Phosphoric acid
Answer: Hydrochloric acid (HCl) completely ionizes in water, making it a strong acid.
Chemistry
A. [Ar] 3d6
B. [Ar] 3d5
C. [Ar] 3d4
D. [Ar] 3d6 4s2
Answer: Fe has configuration [Ar] 3d6 4s2; losing 2 electrons from 4s gives [Ar] 3d6.
Chemistry
A. 2, 8, 2
B. 2, 8, 1
C. 2, 8, 7
D. 2, 7, 1
Answer: Sodium has 11 electrons arranged as 2, 8, 1 giving it one valence electron.
Chemistry
A. Zero
B. 1 kJ/mol
C. -1 kJ/mol
D. Depends on the element
Answer: By convention, the standard enthalpy of formation of an element in its most stable form is zero.
Chemistry
A. Increases down the group
B. Decreases down the group
C. Remains constant
D. First increases then decreases
Answer: Atomic radius increases down a group because new electron shells are added at each period.
Chemistry
A. 0.5 mole
B. 1 mole
C. 2 moles
D. 1.5 moles
Answer: CaCO3 to CaO + CO2 is a 1:1 reaction, so 1 mole produces 1 mole of CO2.
Chemistry
A. Sugar solution
B. Sodium chloride solution
C. Distilled water
D. Ethanol
Answer: Sodium chloride solution conducts electricity because it dissociates into Na+ and Cl- ions.
Chemistry
A. 6, 8, 6
B. 6, 6, 8
C. 8, 6, 6
D. 6, 14, 6
Answer: Carbon-14 has 6 protons, 14 - 6 = 8 neutrons, and 6 electrons (neutral atom).
Chemistry
A. Sodium
B. Chlorine
C. Oxygen
D. Argon
Answer: Chlorine is a halogen and belongs to Group 17 of the periodic table.
Chemistry
A. 11.2 L
B. 22.4 L
C. 44.8 L
D. 2.24 L
Answer: At standard temperature and pressure, 1 mole of an ideal gas occupies 22.4 L.
Chemistry
A. Na
B. KMnO4
C. Fe
D. Cu
Answer: KMnO4 contains Mn in +7 oxidation state and readily accepts electrons, making it a strong oxidizing agent.
Chemistry
A. Electron affinity
B. Ionization energy
C. Electronegativity
D. Lattice energy
Answer: Ionization energy is the minimum energy required to remove the most loosely bound electron from a gaseous atom.
Chemistry
A. Increase in temperature
B. Decrease in temperature
C. Increase in pressure only
D. No change
Answer: Gas solubility in water increases as temperature decreases because kinetic energy of gas molecules reduces.
Chemistry
A. Methanoic acid
B. Ethanoic acid
C. Propanoic acid
D. Ethanal
Answer: CH3COOH has a two-carbon chain with a carboxyl group, giving it the IUPAC name ethanoic acid.
Chemistry
A. 2, 8, 7
B. 2, 8, 8
C. 2, 8, 6
D. 2, 7, 8
Answer: Chlorine gains one electron to form Cl-, giving it 18 electrons arranged as 2, 8, 8 like argon.
Chemistry
A. NaCl
B. CCl4
C. KBr
D. MgO
Answer: CCl4 is formed by sharing electrons between carbon and chlorine atoms, making it covalent.
Chemistry
A. Vanadium pentoxide
B. Iron
C. Platinum
D. Manganese dioxide
Answer: Iron is used as a catalyst in the Haber process for the synthesis of ammonia from N2 and H2.
Chemistry
A. Melting
B. Sublimation
C. Condensation
D. Evaporation
Answer: Sublimation is the phase transition where a solid changes directly into gas without becoming liquid.
Chemistry
A. CH2=CH2 + H2 to CH3CH3
B. CH4 + Cl2 to CH3Cl + HCl
C. 2CH3CH2OH to CH3CH2OCH2CH3 + H2O
D. CH3COOH + NaOH to CH3COONa + H2O
Answer: In this reaction, hydrogen adds across the double bond of ethene to form ethane.
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