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Showing 305 MCQs in Chemistry
Chemistry
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.
Chemistry
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.
Chemistry
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.
Chemistry
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).
Chemistry
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.
Chemistry
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.
Chemistry
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.
Chemistry
A. 0
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.
Chemistry
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.
Chemistry
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).
Chemistry
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.
Chemistry
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.
Chemistry
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.
Chemistry
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.
Chemistry
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.
Chemistry
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.
Chemistry
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).
Chemistry
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.
Chemistry
A. -2
B. -1
C. +1
D. 0
Answer: In peroxides (like H2O2 and Na2O2), oxygen has an oxidation state of -1 because the O-O bond involves shared electrons equally.
Chemistry
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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