All Free Chemistry MCQs with Answers

• A. (PB+2)(2CL-).
• B. (PB+2)(CL-)2
• C. (PB+2)(CL-2).
• D. (PB)(CL).

Explanation: The solubility product constant (Ksp) of lead(II) chloride (PbCl2) is approximately 1.6 x 10-5 at 25°C.

• A. Formation of ester
• B. Dissociation of PCl5
• C. Decomposition of N2O4
• D. Synthesis of NH3

Explanation: This is typically a liquid-phase reaction involving liquids (like acid + alcohol → ester + water).Volume changes do not significantly…

• A. No ammonia will form.
• B. % of NH3 will be low
• C. Catalyst would be of no use
• D. Rate or formation will be very slow

Explanation: Lower temperature slows down reaction kinetics significantly, so even though equilibrium favors NH3 at lower T, the reaction rate is very…

• A. Kc > 1
• B. Kc = 1
• C. Kc < 1
• D. Cannot be predicted from how quickly equilibrium is attained

Explanation: None of the four choices can be predicted from the fact that equilibrium is attained quickly.

• A. AgBrO3 > Ag2SO4
• B. AgBrO3 < Ag2SO4
• C. AgBrO3 = Ag2SO4
• D. AgBrO3 << Ag2SO4

Explanation: Matches the calculation: Ag₂SO₄ has the larger solubility value (~0.017) vs AgBrO₃ (~0.007). So AgBrO₃ < Ag₂SO₄.

• A. MA Ksp = 1.8 × 10⁻¹⁰
• B. MB - Ksp = 4 × 10⁻³
• C. MC - Ksp = 4 × 10⁻⁵
• D. MD - Ksp = 6 × 10⁻⁵

Explanation: Smallest Ksp → least soluble → precipitates first.Here, MA has the smallest Ksp (1.8×10−10), so MA comes out first when MX is added

• A. Stand still
• B. Slow down
• C. Speed up in reverse direction
• D. Move towards the right.

Explanation: According to Le Chatelier's Principle,If you increase the concentration of reactants, the equilibrium will shift in the direction that…

• A. Increase in V (Volume)
• B. Increase in P (Pressure)
• C. Change in T (Temperature)
• D. Catalyst

Explanation: Increase in volume - YES (affects equilibrium position and concentration/rate)Increase in pressure - YES (affects equilibrium position and…

• A. Waterloo in 1815. The French was defeated at
• B. The French were defeated at Waterloo in 1815.
• C. French were defeated at Waterloo in 1815.
• D. The French men were defeated at Waterloo on 1815.

Explanation: The sentence is describing a historical event, and the correct form is to use the plural subject "The French" with the plural verb "were".

• A. The majority of the university faculty have formed into factions, some supporting the university's president, and others calling for his ouster.
• B. The majority of the university faculty has formed into factions, some supporting the university's president, and others calling for his ouster.
• C. The majority of the university faculty have formed to factions, some supporting the university's president, and others calling for his ouster.
• D. A majority of the university faculty has formed into factions, some supporting the university's president, and others calling for his ouster.

Explanation: The correct answer is Option B: 'The majority of the university faculty has formed into factions, some supporting the university's…

• A. Halogenation
• B. Hydrogenation
• C. Hydroxylation
• D. Dehydrogenation

Explanation: Hydrogenation of alkenes or alkynes in the presence of nickel at 200-300*C yields alkanes.

• A. cis-trans isomerism
• B. geometric isomerism
• C. both
• D. none

Explanation: Propene (C3H6) is an example of an alkene, and it has a carbon-carbon double bond.

• A. low b.p
• B. low vapor pressure
• C. high b.p
• D. high electrical conductivity

Explanation: Organic compounds that are essentially nonpolar and exhibit weak intermolecular forces tend to have low vapor pressure.

• A. organic compounds can be synthesized from inorganic compounds
• B. organic compounds cannot be synthesized from inorganic compounds
• C. organic compounds can be synthesized by animals
• D. organic compounds can be synthesized by plants

Explanation: Vital force theory, proposed by Jöns Jacob Berzelius in the early 19th century, stated that:Organic compounds originated solely from…

• A. two sigma bonds
• B. two pi bonds
• C. one sigma and one pi bond
• D. one sigma and two pi bond

Explanation: A double bond is formed by the combination of one sigma bond, resulting from head-on orbital overlap, and one pi bond, resulting from…

• A. knocking
• B. reforming
• C. cracking
• D. both a and c

Explanation: The metallic sound produced by the pre-ignition of fuel in an engine is commonly referred to as knocking.

• A. PbCl2
• B. (C2H5)4Pb
• C. (C2H5)2Pb
• D. all of the above

Explanation: Tetraethyl lead, represented as (C2H5)4Pb, is a well-known anti-knocking agent that was historically used in gasoline.

• A. metamerism
• B. functional group isomerism
• C. geometric isomerism
• D. positional isomerism

Explanation: Positional isomerism involves isomers that differ in the position of a functional group or substituent on the carbon chain.

• A. Cr2O3 + Al2O3 + SiO2
• B. Raney nickel
• C. Organo-nickel
• D. Ni 250 - 300°C

Explanation: The preparation of benzene from acetylene at 70°C typically employs an organo-nickel catalyst.

• A. Heating sodium salt of benzoic acid with soda lime
• B. Distilling phenol with Zn dust
• C. Chlorobenzene with NaOH at 360°C & 150 atm.
• D. Hydrolysis of benzene sulfonic acid with superheated steam

Explanation: The mixture of catalysts Cr2O3 + Al2O3 + SiO2 is used when benzene is produced from acetylene at elevated temperatures (500°C).The mixture…