A solution is a homogeneous mixture of
A two or more substances
B only solids
C only liquids
D only gases
Solution is a single-phase homogeneous mixture of solute(s) and solvent.
The component present in larger amount in a solution is called
A solute
B solvent
C precipitate
D adsorbent
Solvent is the medium that dissolves solute and is present in greater amount.
Which of the following is an example of solid in liquid solution
A air
B brass
C sugar in water
D hydrogen in palladium
Sugar (solid) dissolves in water (liquid) to form a solution.
A solution of gas in liquid is
A soda water
B brass
C fog
D smoke
CO₂ dissolved in water forms soda water.
A solution of solid in solid is
A salt water
B brass
C vinegar
D milk
Brass is an alloy (Zn dissolved in Cu), a solid-solid solution.
Concentration expressed as moles of solute per liter of solution is
A molality
B molarity
C mole fraction
D normality
Molarity (M) = moles of solute / volume of solution in liters.
Molality is defined as
A moles of solute per liter of solution
B moles of solute per kg of solvent
C grams of solute per liter of solution
D grams of solute per kg of solution
Molality (m) uses mass of solvent, hence temperature independent.
Which concentration term is temperature independent
A molarity
B molality
C normality
D formality
Mass of solvent doesn’t change with temperature, but volume does.
Mole fraction of a component is
A moles of component / total moles of solution
B mass of component / total mass
C volume of component / total volume
D moles of solvent / moles of solute
Mole fraction is ratio of moles of a component to total moles.
Parts per million (ppm) is used to express concentration of
A very concentrated solutions
B very dilute solutions
C only gases
D only solids
ppm is convenient for trace amounts (e.g., pollutants in water).
Raoult’s law for ideal solutions states that partial vapor pressure of a component is
A directly proportional to its mole fraction
B inversely proportional to its mole fraction
C independent of mole fraction
D proportional to molality
Raoult’s law: PA=XAPA0P_A = X_A P_A^0PA=XAPA0.
The vapor pressure of a pure liquid at a given temperature is
A P°
B X
C K
D π
Standard vapor pressure of pure solvent is written as P0P^0P0.
Lowering of vapor pressure is a
A colligative property
B chemical property
C kinetic property
D surface property
Colligative properties depend only on number of solute particles.
For non-volatile solute, relative lowering of vapor pressure equals
A mole fraction of solute
B mole fraction of solvent
C molarity of solute
D molality of solvent
(P0−P)/P0=Xsolute(P^0 – P)/P^0 = X_{solute}(P0−P)/P0=Xsolute.
An ideal solution is one that obeys
A Henry’s law only
B Raoult’s law for all components
C Dalton’s law only
D Boyle’s law only
Ideal solutions follow Raoult’s law at all compositions.
Boiling point elevation depends on
A nature of solute
B number of solute particles
C color of solute
D density of solvent only
Colligative properties depend on particle count, not identity.
Elevation in boiling point is given by
A ΔTb = Kf m
B ΔTb = Kb m
C ΔTb = πV
D ΔTb = RT
Boiling point elevation: ΔTb = Kb × molality.
Depression in freezing point is given by
A ΔTf = Kf m
B ΔTf = Kb m
C ΔTf = RT
D ΔTf = P°X
Freezing point depression: ΔTf = Kf × molality.
Osmotic pressure (π) is given by
A π = MRT
B π = mRT
C π = Kb m
D π = Kf m
For dilute solutions, osmotic pressure behaves like gas pressure: π = MRT.
Reverse osmosis is used for
A increasing solubility
B purification of water
C increasing vapor pressure
D decreasing boiling point
Reverse osmosis removes dissolved salts and impurities from water.
A solution having same osmotic pressure as another solution is
A hypertonic
B hypotonic
C isotonic
D amphoteric
Isotonic solutions have equal osmotic pressure.
Van’t Hoff factor (i) is used to account for
A color change
B association or dissociation of solute
C density change
D pressure change
i corrects colligative properties when solute forms fewer/more particles.
For NaCl in water (ideal dissociation), van’t Hoff factor is nearly
A 0.5
B 1
C 2
D 3
NaCl → Na⁺ + Cl⁻ gives about 2 particles.
For acetic acid showing association (dimerization) in benzene, van’t Hoff factor is
A less than 1
B equal to 1
C greater than 2
D equal to 2
Association reduces number of particles → i < 1.
Which colligative property is most suitable for determining molar mass of macromolecules
A elevation in boiling point
B depression in freezing point
C lowering of vapor pressure
D osmotic pressure
Osmotic pressure is measurable even for very dilute solutions of large molecules.
Adsorption is a phenomenon of accumulation of molecules at
A the bulk of solution
B the surface
C the center of container
D the bottom only
Adsorption occurs on surface; absorption occurs in bulk.
Absorption differs from adsorption because absorption occurs in
A surface only
B bulk of material
C gas phase only
D liquid phase only
Absorption is uniform penetration into the bulk.
Physical adsorption is also called
A chemisorption
B van der Waals adsorption
C ionic adsorption
D covalent adsorption
Physical adsorption is due to weak van der Waals forces.
Chemisorption is characterized by
A low heat of adsorption
B multilayer formation
C high specificity and high heat of adsorption
D reversible at all temperatures
Chemisorption involves chemical bond formation → strong and specific.
Freundlich adsorption isotherm is
A P = k
B x/m = kP^(1/n)
C x/m = KP
D PV = nRT
Freundlich isotherm relates adsorption (x/m) to pressure (P) for gases.
Activated charcoal is used in gas masks due to
A absorption
B adsorption
C osmosis
D diffusion
Charcoal adsorbs poisonous gases due to large surface area.
Catalyst increases reaction rate by
A increasing ΔG
B decreasing activation energy
C increasing equilibrium constant
D converting products back to reactants
Catalysts provide an alternate pathway with lower Ea.
A catalyst does not change
A activation energy
B rate of reaction
C equilibrium constant
D time to reach equilibrium
Catalyst affects kinetics (rate) not thermodynamics (K).
Enzymes are examples of
A homogeneous catalysts
B biological catalysts
C negative catalysts
D inhibitors only
Enzymes are proteins that catalyze biochemical reactions.
Poisoning of catalyst means
A catalyst increases activity
B catalyst surface becomes inactive due to impurities
C catalyst changes equilibrium constant
D catalyst becomes soluble
Impurities block active sites and reduce catalytic activity.
Colloids have particle size in range
A < 1 nm
B 1–1000 nm
C 1–10 μm
D > 1000 μm
Colloidal particles lie between true solution and suspension size.
Tyndall effect is shown by
A true solutions
B colloidal solutions
C pure solvents only
D crystalline solids
Scattering of light by colloidal particles causes Tyndall effect.
Brownian motion in colloids is due to
A gravity
B collisions with dispersion medium molecules
C magnetic force
D chemical reactions
Random collisions cause zig-zag motion of colloidal particles.
Coagulation of colloids means
A making particles smaller
B precipitation of colloidal particles
C increasing transparency
D increasing diffusion
Coagulation is aggregation leading to settling of particles.
An emulsion is a colloid of
A solid in gas
B liquid in liquid
C gas in solid
D solid in solid
Emulsions are dispersions of one liquid in another.
Milk is an example of
A aerosol
B foam
C emulsion
D gel
Milk is oil/fat droplets dispersed in water.
Sol is a colloid of
A solid in liquid
B liquid in solid
C gas in liquid
D gas in solid
Sol: solid dispersed phase in liquid medium (e.g., paint).
Gel is a colloid of
A solid in liquid
B liquid in solid
C gas in solid
D solid in gas
Gel: liquid trapped in a solid network (e.g., jelly).
Which electrolyte causes maximum coagulation according to Hardy–Schulze rule
A Na⁺
B Ca²⁺
C Al³⁺
D K⁺
Higher valency counter-ions have greater coagulating power.
Dialysis is used to
A increase colloid concentration
B remove electrolytes from colloids
C form precipitate
D increase particle size
Dialysis removes dissolved ions through semipermeable membrane.
Electrophoresis in colloids refers to
A movement of colloidal particles under electric field
B movement of solvent only
C scattering of light
D settling by gravity
Charged colloidal particles migrate in electric field.
Lyophilic colloids are
A easily formed and more stable
B unstable and easily coagulated
C always negatively charged
D always solid sols
Lyophilic colloids have strong affinity for dispersion medium → stable.
Lyophobic colloids are
A very stable
B require special methods for preparation
C always gels
D always emulsions
Lyophobic colloids have little affinity for medium and are unstable.
A colloid used to remove smoke particles from air is based on
A dialysis
B adsorption
C electrostatic precipitation
D osmosis
Cottrell precipitator removes smoke using electric field.
Protective colloids prevent coagulation by
A increasing particle size
B forming a protective layer on particles
C decreasing surface charge always
D increasing temperature
Protective colloids stabilize lyophobic sols by coating particles.