Q. What is the relationship between ΔH and ΔG at equilibrium?
-
A.
ΔG = 0
-
B.
ΔH = 0
-
C.
ΔG = ΔH
-
D.
ΔG = ΔH + TΔS
Solution
At equilibrium, the change in Gibbs free energy (ΔG) is zero.
Correct Answer: A — ΔG = 0
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Q. What is the relationship between ΔH and ΔU for a reaction at constant pressure?
-
A.
ΔH = ΔU + PΔV
-
B.
ΔH = ΔU - PΔV
-
C.
ΔH = ΔU
-
D.
ΔH = PΔV
Solution
At constant pressure, the relationship is given by ΔH = ΔU + PΔV.
Correct Answer: A — ΔH = ΔU + PΔV
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Q. What is the repeating unit in polyethylene?
-
A.
-CH2-CH2-
-
B.
-C6H5-
-
C.
-C3H6-
-
D.
-C2H4-
Solution
The repeating unit in polyethylene is -CH2-CH2-, derived from ethylene monomers.
Correct Answer: A — -CH2-CH2-
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Q. What is the role of a catalyst in a redox reaction?
-
A.
Increase oxidation
-
B.
Increase reduction
-
C.
Speed up the reaction
-
D.
Change the products
Solution
A catalyst speeds up the reaction without being consumed in the process.
Correct Answer: C — Speed up the reaction
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Q. What is the role of a salt bridge in a galvanic cell?
-
A.
To provide a pathway for electrons
-
B.
To maintain charge balance
-
C.
To increase voltage
-
D.
To decrease resistance
Solution
The salt bridge maintains charge balance by allowing ions to flow between the two half-cells.
Correct Answer: B — To maintain charge balance
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Q. What is the role of activated charcoal in adsorption processes?
-
A.
Catalyst
-
B.
Adsorbent
-
C.
Solvent
-
D.
Reagent
Solution
Activated charcoal is commonly used as an adsorbent due to its high surface area and porosity.
Correct Answer: B — Adsorbent
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Q. What is the role of antioxidants in food?
-
A.
Enhancing flavor
-
B.
Preventing spoilage
-
C.
Reducing oxidation
-
D.
Increasing acidity
Solution
Antioxidants prevent oxidation, which can spoil food and reduce its nutritional value.
Correct Answer: C — Reducing oxidation
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Q. What is the role of antioxidants in the body?
-
A.
Increase energy
-
B.
Prevent oxidation
-
C.
Enhance digestion
-
D.
Boost immunity
Solution
Antioxidants prevent oxidation, which can damage cells and lead to various diseases.
Correct Answer: B — Prevent oxidation
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Q. What is the role of ATP in cells?
-
A.
Storage of genetic information
-
B.
Energy currency
-
C.
Structural component
-
D.
Signal transduction
Solution
ATP (adenosine triphosphate) serves as the primary energy currency in cells.
Correct Answer: B — Energy currency
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Q. What is the role of caffeine in coffee?
-
A.
Antioxidant
-
B.
Stimulant
-
C.
Sedative
-
D.
Digestive aid
Solution
Caffeine acts as a stimulant, increasing alertness and reducing fatigue.
Correct Answer: B — Stimulant
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Q. What is the role of chlorofluorocarbons (CFCs) in environmental chemistry?
-
A.
Ozone depletion
-
B.
Greenhouse gas effect
-
C.
Acid rain formation
-
D.
Water pollution
Solution
CFCs are known to deplete the ozone layer, leading to increased UV radiation reaching the Earth's surface.
Correct Answer: A — Ozone depletion
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Q. What is the role of emulsifiers in food products?
-
A.
Thickeners
-
B.
Stabilizers
-
C.
Flavor enhancers
-
D.
Coloring agents
Solution
Emulsifiers help to stabilize mixtures of oil and water in food products.
Correct Answer: B — Stabilizers
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Q. What is the role of enzymes in biochemical reactions?
-
A.
Increase activation energy
-
B.
Decrease activation energy
-
C.
Change the equilibrium of the reaction
-
D.
Provide energy for the reaction
Solution
Enzymes act as catalysts that decrease the activation energy required for biochemical reactions.
Correct Answer: B — Decrease activation energy
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Q. What is the role of enzymes in biological systems?
-
A.
To provide structural support
-
B.
To act as catalysts for biochemical reactions
-
C.
To store genetic information
-
D.
To transport molecules across membranes
Solution
Enzymes are proteins that act as catalysts, speeding up biochemical reactions without being consumed in the process.
Correct Answer: B — To act as catalysts for biochemical reactions
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Q. What is the role of histamines in the body?
-
A.
To promote sleep
-
B.
To regulate blood sugar
-
C.
To trigger allergic reactions
-
D.
To enhance digestion
Solution
Histamines are chemicals that play a key role in allergic reactions.
Correct Answer: C — To trigger allergic reactions
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Q. What is the role of RNA in protein synthesis?
-
A.
Storage of genetic information
-
B.
Transcription of DNA
-
C.
Translation of proteins
-
D.
Both transcription and translation
Solution
RNA plays a crucial role in both the transcription of DNA and the translation of proteins.
Correct Answer: D — Both transcription and translation
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Q. What is the role of the cathode in an electrochemical cell?
-
A.
Oxidation occurs
-
B.
Reduction occurs
-
C.
Electrons are lost
-
D.
Ions are produced
Solution
In an electrochemical cell, reduction occurs at the cathode.
Correct Answer: B — Reduction occurs
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Q. What is the shape of a molecule with the formula AX3E?
-
A.
Trigonal planar
-
B.
Tetrahedral
-
C.
Trigonal pyramidal
-
D.
Bent
Solution
AX3E indicates three bonding pairs and one lone pair, resulting in a trigonal pyramidal shape.
Correct Answer: C — Trigonal pyramidal
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Q. What is the shape of the ammonia (NH3) molecule?
-
A.
Linear
-
B.
Trigonal planar
-
C.
Tetrahedral
-
D.
Trigonal pyramidal
Solution
Ammonia has a trigonal pyramidal shape due to the presence of a lone pair on the nitrogen atom.
Correct Answer: D — Trigonal pyramidal
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Q. What is the shape of the d orbitals?
-
A.
Spherical
-
B.
Dumbbell
-
C.
Double dumbbell
-
D.
Linear
Solution
The d orbitals have a double dumbbell shape.
Correct Answer: C — Double dumbbell
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Q. What is the shape of the molecular orbital in the case of a π bond?
-
A.
Spherical
-
B.
Dumbbell
-
C.
Linear
-
D.
Planar
Solution
π bonds are formed by the side-to-side overlap of p orbitals, resulting in a planar shape.
Correct Answer: D — Planar
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Q. What is the shape of the molecular orbital in the highest occupied molecular orbital (HOMO) of benzene?
-
A.
Linear
-
B.
Trigonal planar
-
C.
Tetrahedral
-
D.
Cyclic
Solution
The HOMO of benzene is cyclic due to the delocalization of π electrons in the ring structure.
Correct Answer: D — Cyclic
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Q. What is the shape of the molecular orbital of the highest energy in O2?
-
A.
spherical
-
B.
dumbbell
-
C.
double dumbbell
-
D.
linear
Solution
The highest energy molecular orbital in O2 is a π* orbital, which has a dumbbell shape.
Correct Answer: B — dumbbell
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Q. What is the shape of the molecular orbital of the highest energy in the O2 molecule?
-
A.
Linear
-
B.
Bent
-
C.
Planar
-
D.
Diatomic
Solution
The highest energy molecular orbital in O2 is a diatomic molecular orbital, specifically a π* orbital.
Correct Answer: D — Diatomic
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Q. What is the shape of the molecule PCl5?
-
A.
Trigonal bipyramidal
-
B.
Octahedral
-
C.
Tetrahedral
-
D.
Square planar
Solution
PCl5 has a trigonal bipyramidal shape due to five bonding pairs around the phosphorus atom.
Correct Answer: A — Trigonal bipyramidal
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Q. What is the shape of the molecule SF6 according to VSEPR theory?
-
A.
Square planar
-
B.
Octahedral
-
C.
Trigonal bipyramidal
-
D.
Tetrahedral
Solution
SF6 has six bonding pairs and no lone pairs, leading to an octahedral shape.
Correct Answer: B — Octahedral
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Q. What is the shape of the molecule with the formula AX2E2 according to VSEPR theory?
-
A.
Linear
-
B.
Bent
-
C.
Trigonal planar
-
D.
Tetrahedral
Solution
AX2E2 indicates two bonding pairs and two lone pairs, resulting in a bent shape.
Correct Answer: B — Bent
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Q. What is the shape of the molecule with the formula AX3E?
-
A.
Tetrahedral
-
B.
Trigonal pyramidal
-
C.
Trigonal planar
-
D.
Bent
Solution
AX3E indicates three bonding pairs and one lone pair, resulting in a trigonal pyramidal shape.
Correct Answer: B — Trigonal pyramidal
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Q. What is the shape of the molecule with the formula AX4?
-
A.
Tetrahedral
-
B.
Square planar
-
C.
Trigonal bipyramidal
-
D.
Octahedral
Solution
AX4 indicates four bonding pairs and no lone pairs, resulting in a tetrahedral shape.
Correct Answer: A — Tetrahedral
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Q. What is the shape of the p-orbital?
-
A.
Spherical
-
B.
Dumbbell
-
C.
Double dumbbell
-
D.
Linear
Solution
The p-orbital has a dumbbell shape.
Correct Answer: B — Dumbbell
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