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Showing 305 MCQs in Chemistry
Chemistry
A. Bromine (Br)
B. Chlorine (Cl)
C. Iodine (I)
D. Fluorine (F)
Answer: The configuration [Ar] 3d10 4s2 4p5 has 35 electrons, which corresponds to Bromine (Z = 35).
Chemistry
A. C6H12O6
B. C6H10O5
C. C12H22O11
D. CH2O
Answer: Glucose is a monosaccharide with the molecular formula C6H12O6, containing six carbon atoms, twelve hydrogen atoms, and six oxygen atoms.
Chemistry
A. +1.00 V
B. 0.00 V
C. -1.00 V
D. +0.76 V
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.
Chemistry
A. Boyle\'s law
B. Charles\'s law
C. Avogadro\'s law
D. Dalton\'s law
Answer: Charles\'s law states V ∝ T (at constant P and n), meaning volume increases linearly with absolute temperature.
Chemistry
A. CH3OH
B. CH3COOH
C. CH3CHO
D. CH3OCH3
Answer: Dimethyl ether (CH3OCH3) has an oxygen atom bonded to two alkyl groups, characterizing an ether.
Chemistry
A. Methanol
B. Ethanol
C. Propanol
D. Ethanal
Answer: CH3-CH2-OH has a two-carbon chain with a hydroxyl group, so its IUPAC name is ethanol (ethan-1-ol).
Chemistry
A. -2
B. +1
C. 0
D. -1
Answer: In peroxides such as H2O2, oxygen has an oxidation state of -1 instead of the usual -2.
Chemistry
A. Covalent bonding
B. Ionic bonding
C. Metallic bonding
D. Hydrogen bonding
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.
Chemistry
A. sp
B. sp2
C. sp3
D. sp3d
Answer: Carbon in CH4 forms four sigma bonds with no lone pairs, giving sp3 hybridization and tetrahedral geometry.
Chemistry
A. Principal quantum number (n)
B. Azimuthal quantum number (l)
C. Magnetic quantum number (ml)
D. Spin quantum number (ms)
Answer: The azimuthal quantum number (l) determines the shape of an orbital: l=0 is s (spherical), l=1 is p (dumbbell), etc.
Chemistry
A. 4 sigma, 1 pi
B. 5 sigma, 1 pi
C. 4 sigma, 2 pi
D. 5 sigma, 0 pi
Answer: Ethene has 4 C-H sigma bonds + 1 C-C sigma bond = 5 sigma bonds, and 1 C=C pi bond.
Chemistry
A. 6
B. 8
C. 14
D. 10
Answer: Carbon-14 has atomic number 6 (protons = 6) and mass number 14. Neutrons = 14 - 6 = 8.
Chemistry
A. 1
B. 2
C. 3
D. 4
Answer: HCl is a strong acid that fully dissociates. [H+] = 0.001 M = 10^-3, so pH = -log(10^-3) = 3.
Chemistry
A. NH3
B. OH-
C. BF3
D. CH3O-
Answer: BF3 is electron-deficient (boron has only 6 electrons) and can accept an electron pair, making it an electrophile.
Chemistry
A. NaCl
B. Na2CO3
C. NaHCO3
D. NaNO2
Answer: Sodium nitrite (NaNO2) is used as a preservative in cured meats to prevent bacterial growth.
Chemistry
A. 0.1 M NaCl
B. 0.1 M glucose
C. 0.1 M CaCl2
D. 0.1 M urea
Answer: Boiling point elevation depends on the number of solute particles. CaCl2 dissociates into 3 ions (i=3), producing the greatest elevation.
Chemistry
A. Ethanol
B. Chloroform
C. Acetone
D. Iodoform
Answer: Iodoform (CHI3) has mild antiseptic properties and is used on wounds and burns.
Chemistry
A. +3
B. +4
C. +6
D. +7
Answer: In K2Cr2O7: 2(+1) + 2(Cr) + 7(-2) = 0, so 2Cr = 12, Cr = +6.
Chemistry
A. Sodium (Na)
B. Magnesium (Mg)
C. Oxygen (O)
D. Chlorine (Cl)
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).
Chemistry
A. Li
B. B
C. C
D. Be
Answer: Be has a filled 2s orbital, making it more stable and harder to ionize than adjacent elements.
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