Chemistry MDCAT
Organic, inorganic & physical chemistry MCQs
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Chemistry
MDCAT Chemistry MCQs — organic, inorganic & physical chemistry
Answer: In peroxides such as H2O2, oxygen has an oxidation state of -1 instead of the usual -2.
Answer: Sodium nitrite (NaNO2) is used as a preservative in cured meats to prevent bacterial growth.
Answer: Dimethyl ether (CH3OCH3) has an oxygen atom bonded to two alkyl groups, characterizing an ether.
Answer: Iodoform (CHI3) has mild antiseptic properties and is used on wounds and burns.
Answer: Be has a filled 2s orbital, making it more stable and harder to ionize than adjacent elements.
Answer: Carbon in CH4 forms four sigma bonds with no lone pairs, giving sp3 hybridization and tetrahedral geometry.
Answer: Carbon-14 has atomic number 6 (protons = 6) and mass number 14. Neutrons = 14 - 6 = 8.
Answer: The azimuthal quantum number (l) determines the shape of an orbital: l=0 is s (spherical), l=1 is p (dumbbell), etc.
Answer: Oxygen has an electronegativity of 3.44 on the Pauling scale, which is higher than Na (0.93), Mg (1.31), and Cl (3.16).
Answer: Glucose is a monosaccharide with the molecular formula C6H12O6, containing six carbon atoms, twelve hydrogen atoms, and six oxygen atoms.
Answer: NaCl is formed by the transfer of an electron from Na to Cl, creating Na+ and Cl- ions held together by electrostatic (ionic) forces.
Answer: In K2Cr2O7: 2(+1) + 2(Cr) + 7(-2) = 0, so 2Cr = 12, Cr = +6.
Answer: Charles\'s law states V ∠T (at constant P and n), meaning volume increases linearly with absolute temperature.
Answer: HCl is a strong acid that fully dissociates. [H+] = 0.001 M = 10^-3, so pH = -log(10^-3) = 3.
Answer: The configuration [Ar] 3d10 4s2 4p5 has 35 electrons, which corresponds to Bromine (Z = 35).
Answer: CH3-CH2-OH has a two-carbon chain with a hydroxyl group, so its IUPAC name is ethanol (ethan-1-ol).
Answer: BF3 is electron-deficient (boron has only 6 electrons) and can accept an electron pair, making it an electrophile.
Answer: Ethene has 4 C-H sigma bonds + 1 C-C sigma bond = 5 sigma bonds, and 1 C=C pi bond.
Answer: Boiling point elevation depends on the number of solute particles. CaCl2 dissociates into 3 ions (i=3), producing the greatest elevation.
Answer: The Standard Hydrogen Electrode (SHE) is assigned a potential of exactly 0.00 V by convention and serves as the reference for all other electrodes.