Chemistry MDCAT

Organic, inorganic & physical chemistry MCQs

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Chemistry

MDCAT Chemistry MCQs — organic, inorganic & physical chemistry

305 MCQs Page 8 of 16
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A. But-1-ene
B. But-2-ene
C. Butane
D. But-1,3-diene
Answer: The double bond starts at carbon 2 in the four-carbon chain, so the IUPAC name is but-2-ene.
A. H2O
B. NH3
C. CCl4
D. HCl
Answer: CCl4 has a tetrahedral geometry with four identical C-Cl bonds. The bond dipoles cancel out, making the molecule nonpolar.
A. 22.4 L
B. 24.5 L
C. 11.2 L
D. 44.8 L
Answer: At STP (0 degrees C, 1 atm), 1 mole of an ideal gas occupies 22.4 liters according to Avogadro\'s law.
A. NH3
B. H2O
C. AlCl3
D. OH-
Answer: AlCl3 has an incomplete octet on aluminum, allowing it to accept an electron pair, which defines a Lewis acid.
A. 2
B. 3
C. 4
D. 5
Answer: C6H4Cl2 has three positional isomers: 1,2-dichlorobenzene (ortho), 1,3-dichlorobenzene (meta), and 1,4-dichlorobenzene (para).
A. Atomic radius
B. Ionization energy
C. Metallic character
D. Electronegativity
Answer: Electronegativity generally increases across a period because effective nuclear charge increases, attracting bonding electrons more strongly.
A. 1 N
B. 2 N
C. 3 N
D. 4 N
Answer: H3PO4 is triprotic (3 replaceable H+ ions). Normality = Molarity x n-factor = 1 x 3 = 3 N.
A. Polyethylene
B. Nylon-6,6
C. Polypropylene
D. Polystyrene
Answer: Nylon-6,6 is formed by condensation of adipic acid and hexamethylenediamine with loss of water, making it a condensation polymer.
A. -2
B. -1
C. +1
Answer: In peroxides (like H2O2 and Na2O2), oxygen has an oxidation state of -1 because the O-O bond involves shared electrons equally.
A. Na
B. Mg
C. Al
D. Si
Answer: Mg has a stable 3s2 fully filled subshell, making its first ionization energy higher than Na (3s1), Al (3s2 3p1), and Si (3s2 3p2).
A. H-O-H with two lone pairs on O
B. H-O-H with one lone pair on O
C. H=O with two lone pairs on O
D. H-O-H with no lone pairs
Answer: Water has two O-H bonds and two lone pairs on oxygen, giving it a bent molecular geometry.
A. Ethane
B. Ethene
C. Benzene
D. Methane
Answer: Ethene (an alkene with a C=C double bond) undergoes addition reactions because the pi bond is relatively weak and can be broken to add atoms.
A. 0.1 M
B. 0.2 M
C. 0.5 M
D. 1.0 M
Answer: Moles of NaCl = 5.85/58.5 = 0.1 mol. Molarity = 0.1 mol / 0.5 L = 0.2 M.
A. SO2
B. CO2
C. CaO
D. Cl2O7
Answer: CaO is a basic oxide formed from a metal (Ca). It reacts with water to form Ca(OH)2 and with acids to form salts.
B. 1
C. 2
D. 3
Answer: Cl has 7 valence electrons. Three are used for bonding with F, leaving 4 electrons = 2 lone pairs, giving a T-shaped molecular geometry.
A. C2H2 < C2H4 < C2H6
B. C2H6 < C2H4 < C2H2
C. C2H4 < C2H2 < C2H6
D. C2H2 = C2H4 = C2H6
Answer: Bond length increases as bond order decreases: C-C triple bond (C2H2) < C=C double bond (C2H4) < C-C single bond (C2H6).
A. Methyl orange
B. Alizarin
C. Indigo
D. Aniline yellow
Answer: Alizarin is a mordant dye that requires a metallic mordant (like aluminum hydroxide) to bind to fabric, producing a vivid red color.
A. 180 degrees
B. 120 degrees
C. 104.5 degrees
D. 109.5 degrees
Answer: Water has sp3 hybridization with two bonding pairs and two lone pairs. The lone pair repulsion compresses the H-O-H angle from 109.5 to about 104.5 degrees.
A. HCl < HBr < HI
B. HI < HBr < HCl
C. HCl > HBr > HI
D. HBr < HCl < HI
Answer: Acidic strength of hydrohalic acids increases down the group (HCl < HBr < HI) because bond dissociation energy decreases as atomic size increases.
A. 1 mole
B. 2 moles
C. 0.5 mole
D. 3 moles
Answer: Molar mass of H2O = 18 g/mol. Moles = 36/18 = 2 moles.
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