Chemistry (School & UG)
Q. What is the primary factor affecting the periodic trends in atomic size?
A.
Nuclear charge
B.
Electron shielding
C.
Electron affinity
D.
Electronegativity
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Solution
Electron shielding affects the effective nuclear charge felt by outer electrons, influencing atomic size.
Correct Answer: B — Electron shielding
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Q. What is the primary factor affecting the rate of a surface reaction?
A.
Surface area of the reactants
B.
Temperature of the reactants
C.
Concentration of the reactants
D.
Pressure of the reactants
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Solution
The rate of a surface reaction is primarily affected by the surface area of the reactants available for reaction.
Correct Answer: A — Surface area of the reactants
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Q. What is the primary factor affecting the rate of a titration reaction?
A.
Concentration of reactants
B.
Temperature of the solution
C.
Volume of the titrant
D.
All of the above
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Solution
The rate of a titration reaction is affected by the concentration of reactants, temperature, and the volume of titrant added.
Correct Answer: D — All of the above
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Q. What is the primary factor that affects the rate of diffusion of a gas?
A.
Molar mass of the gas
B.
Temperature of the gas
C.
Pressure of the gas
D.
Volume of the gas
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Solution
The rate of diffusion of a gas is primarily affected by its molar mass; lighter gases diffuse faster than heavier gases according to Graham's law.
Correct Answer: A — Molar mass of the gas
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Q. What is the primary factor that determines the acidity of a compound?
A.
Electronegativity
B.
Molecular weight
C.
Atomic radius
D.
Bond length
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Solution
Electronegativity is the primary factor; higher electronegativity of the atom bonded to hydrogen increases acidity.
Correct Answer: A — Electronegativity
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Q. What is the primary factor that determines the acidity of a solution?
A.
Concentration of hydroxide ions
B.
Concentration of hydrogen ions
C.
Temperature
D.
Pressure
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Solution
The acidity of a solution is primarily determined by the concentration of hydrogen ions (H+).
Correct Answer: B — Concentration of hydrogen ions
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Q. What is the primary factor that determines the atomic radius of an element?
A.
Number of protons
B.
Number of neutrons
C.
Number of electron shells
D.
Number of valence electrons
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Solution
The atomic radius increases with the number of electron shells, as each additional shell is further from the nucleus.
Correct Answer: C — Number of electron shells
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Q. What is the primary factor that determines the color of transition metal complexes?
A.
The oxidation state of the metal
B.
The type of ligands
C.
The coordination number
D.
The size of the metal ion
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Solution
The type of ligands affects the splitting of d-orbitals, which in turn influences the color of the transition metal complex.
Correct Answer: B — The type of ligands
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Q. What is the primary factor that determines the polarity of a molecule?
A.
Molecular weight
B.
Shape of the molecule
C.
Number of bonds
D.
Type of atoms involved
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Solution
The shape of the molecule determines how bond dipoles add up, affecting overall polarity.
Correct Answer: B — Shape of the molecule
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Q. What is the primary factor that determines the rate of a reaction according to the Arrhenius equation?
A.
Temperature
B.
Concentration
C.
Surface area
D.
Catalyst presence
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Solution
The Arrhenius equation shows that the rate constant increases exponentially with temperature.
Correct Answer: A — Temperature
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Q. What is the primary factor that determines the rate of diffusion of a gas?
A.
Molecular weight
B.
Temperature
C.
Pressure
D.
Volume
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Solution
According to Graham's law of effusion, the rate of diffusion of a gas is inversely proportional to the square root of its molecular weight.
Correct Answer: A — Molecular weight
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Q. What is the primary factor that determines the shape of a molecule according to VSEPR theory?
A.
Electronegativity
B.
Lone pairs of electrons
C.
Molecular weight
D.
Bond length
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Solution
VSEPR theory states that the shape of a molecule is determined by the repulsion between electron pairs, including both bonding and lone pairs.
Correct Answer: B — Lone pairs of electrons
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Q. What is the primary factor that determines the state of matter of a substance?
A.
Temperature
B.
Pressure
C.
Intermolecular forces
D.
Molecular weight
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Solution
The state of matter is primarily determined by the balance between temperature (kinetic energy) and intermolecular forces.
Correct Answer: C — Intermolecular forces
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Q. What is the primary factor that determines the strength of a covalent bond?
A.
Electronegativity
B.
Bond length
C.
Bond order
D.
Molecular weight
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Solution
Bond strength increases with bond order. A higher bond order indicates more shared electron pairs, leading to a stronger bond.
Correct Answer: C — Bond order
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Q. What is the primary function of a burette in titration?
A.
To mix solutions
B.
To measure the volume of titrant added
C.
To heat the solution
D.
To cool the solution
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Solution
A burette is used to accurately measure and deliver the volume of titrant added to the analyte solution.
Correct Answer: B — To measure the volume of titrant added
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Q. What is the primary function of a chromatographic column?
A.
To mix the sample with the mobile phase
B.
To provide a surface for separation
C.
To detect the analytes
D.
To control the temperature
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Solution
The primary function of a chromatographic column is to provide a surface for separation of components based on their interactions with the stationary phase.
Correct Answer: B — To provide a surface for separation
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Q. What is the primary function of a galvanic cell?
A.
Convert chemical energy to electrical energy
B.
Store electrical energy
C.
Generate heat
D.
Facilitate chemical reactions
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Solution
A galvanic cell converts chemical energy from spontaneous redox reactions into electrical energy.
Correct Answer: A — Convert chemical energy to electrical energy
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Q. What is the primary function of a mass spectrometer?
A.
To measure absorbance of light
B.
To separate ions based on their mass-to-charge ratio
C.
To detect electrical conductivity
D.
To analyze pH levels
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Solution
A mass spectrometer separates ions based on their mass-to-charge ratio, allowing for the identification and quantification of different compounds.
Correct Answer: B — To separate ions based on their mass-to-charge ratio
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Q. What is the primary function of a salt bridge in an electrochemical cell?
A.
To provide a source of electrons
B.
To maintain charge balance
C.
To increase conductivity
D.
To facilitate ion exchange
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Solution
The primary function of a salt bridge is to maintain charge balance by allowing ions to flow between the half-cells.
Correct Answer: B — To maintain charge balance
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Q. What is the primary function of baking soda in baking?
A.
Leavening agent
B.
Flavor enhancer
C.
Preservative
D.
Coloring agent
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Solution
Baking soda, or sodium bicarbonate, acts as a leavening agent by producing carbon dioxide when it reacts with acids.
Correct Answer: A — Leavening agent
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Q. What is the primary function of flux in metallurgy?
A.
To increase temperature
B.
To facilitate reduction
C.
To remove impurities
D.
To enhance conductivity
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Solution
Flux is used to remove impurities from metal ores during the smelting process.
Correct Answer: C — To remove impurities
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Q. What is the primary interaction of UV-Vis spectroscopy with a sample?
A.
Scattering of light
B.
Absorption of light
C.
Emission of light
D.
Reflection of light
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Solution
UV-Vis spectroscopy primarily involves the absorption of light by molecules, which promotes electrons to higher energy levels.
Correct Answer: B — Absorption of light
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Q. What is the primary interaction that occurs in UV-Vis spectroscopy?
A.
Vibrational transitions
B.
Rotational transitions
C.
Electronic transitions
D.
Nuclear transitions
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Solution
UV-Vis spectroscopy primarily involves electronic transitions, where electrons are excited from a lower energy level to a higher energy level.
Correct Answer: C — Electronic transitions
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Q. What is the primary mechanism by which addition polymers are formed?
A.
Nucleophilic substitution
B.
Electrophilic addition
C.
Free radical mechanism
D.
Electrophilic substitution
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Solution
Addition polymers are primarily formed through a free radical mechanism, where free radicals initiate the polymerization process.
Correct Answer: C — Free radical mechanism
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Q. What is the primary mechanism by which adsorption occurs on a solid surface?
A.
Physical adsorption
B.
Chemical adsorption
C.
Ion exchange
D.
Covalent bonding
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Solution
Adsorption can occur through physical or chemical means, but chemical adsorption (chemisorption) involves the formation of a chemical bond between the adsorbate and the surface.
Correct Answer: B — Chemical adsorption
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Q. What is the primary method for extracting iron from its ore?
A.
Electrolysis
B.
Carbon reduction
C.
Hydrometallurgy
D.
Biomining
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Solution
Iron is primarily extracted from its ore using carbon reduction in a blast furnace.
Correct Answer: B — Carbon reduction
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Q. What is the primary method of extracting copper from its sulfide ores?
A.
Electrolysis
B.
Roasting
C.
Smelting
D.
Leaching
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Solution
Copper is primarily extracted from its sulfide ores through smelting, where it is heated with a reducing agent.
Correct Answer: C — Smelting
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Q. What is the primary method used to extract aluminum from its ore, bauxite?
A.
Electrolysis
B.
Roasting
C.
Hydrometallurgy
D.
Smelting
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Solution
Aluminum is primarily extracted from bauxite through electrolysis, specifically using the Bayer process followed by electrolysis of alumina.
Correct Answer: A — Electrolysis
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Q. What is the primary oxidation state of chromium in chromate ions?
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Solution
In chromate ions (CrO4^2-), chromium has an oxidation state of +6.
Correct Answer: D — +6
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Q. What is the primary oxidation state of chromium in Cr2O7^2-?
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Solution
In Cr2O7^2-, chromium is in the +6 oxidation state.
Correct Answer: C — +6
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