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Sample BAC Chemistry Practice Questions

Try these sample questions to review concepts for the BAC Chemistry exam. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1What is the primary organic product obtained from the photochemical mono-chlorination of methane in the presence of ultraviolet light?
A.Chloromethane (CH3Cl)
B.Dichloromethane (CH2Cl2)
C.Trichloromethane (CHCl3)
D.Tetrachloromethane (CCl4)
Explanation: Monochlorination replaces one hydrogen atom of methane with chlorine, yielding CH3Cl and HCl. The reaction proceeds through a radical chain initiated by light; an actual reaction mixture can also contain products of further substitution, even without an overall excess of chlorine.
2How many structural (constitutional) chain isomers exist for the alkane with molecular formula C5H12?
A.3
B.2
C.4
D.5
Explanation: Pentane (C5H12) possesses exactly three structural chain isomers: n-pentane (CH3-CH2-CH2-CH2-CH3), isopentane or 2-methylbutane (CH3-CH(CH3)-CH2-CH3), and neopentane or 2,2-dimethylpropane (C(CH3)4). There are no additional structural arrangements possible for this molecular formula.
3What volume of air (measured at STP, containing 20% O2 by volume) is required for the complete combustion of 44.8 L (measured at STP) of propane gas (C3H8)?
A.1120 L
B.224 L
C.560 L
D.896 L
Explanation: The balanced combustion reaction is C3H8 + 5 O2 -> 3 CO2 + 4 H2O. Since 1 mol of propane reacts with 5 mol of O2, 44.8 L (2.0 mol at STP) of C3H8 requires 44.8 L * 5 = 224 L of pure O2. Because air is 20% oxygen by volume, V(air) = 224 L / 0.20 = 1120 L.
4Which major organic product is formed when gaseous propene reacts with hydrogen chloride (HCl) in the absence of peroxides?
A.2-Chloropropane
B.1-Chloropropane
C.1,2-Dichloropropane
D.1-Chloropropene
Explanation: The electrophilic addition of HCl to an unsymmetrical alkene follows Markovnikov's rule: the electrophile (H+) adds to the carbon with more hydrogen atoms to yield the more stable secondary carbocation intermediate (CH3-CH(+)-CH3). The chloride ion then attacks this carbocation to form 2-chloropropane as the predominant product.
5What is the organic product formed when ethene undergoes mild oxidation with cold, weakly alkaline potassium permanganate solution (Baeyer's reagent)?
A.Ethane-1,2-diol (Ethylene glycol)
B.Ethanal (Acetaldehyde)
C.Ethanoic acid (Acetic acid)
D.Carbon dioxide and water
Explanation: Mild oxidation of alkenes using dilute, cold neutral or weakly alkaline KMnO4 (Baeyer's reagent) cleaves only the pi bond to add two hydroxyl groups across the double bond (syn-dihydroxylation). For ethene (CH2=CH2), this syn-addition yields ethane-1,2-diol (ethylene glycol) while the purple permanganate turns into a brown MnO2 precipitate.
6What mass of bromine (Br2, molar mass = 160 g/mol) reacts quantitatively with 5.60 g of 2-butene (C4H8, molar mass = 56 g/mol) in an addition reaction?
A.16.0 g
B.8.00 g
C.32.0 g
D.80.0 g
Explanation: The addition reaction is CH3-CH=CH-CH3 + Br2 -> CH3-CHBr-CHBr-CH3, exhibiting a 1:1 molar stoichiometry. The amount of 2-butene is n = 5.60 g / 56.0 g/mol = 0.100 mol. Therefore, 0.100 mol of Br2 is consumed, and the required mass is m = 0.100 mol * 160.0 g/mol = 16.0 g.
7Which of the following alkenes can exhibit cis-trans (geometric) isomerism?
A.2-Pentene
B.1-Pentene
C.2-Methyl-2-butene
D.Propene
Explanation: Geometric (cis-trans) isomerism requires that each doubly bonded carbon atom carries two different substituent groups. In 2-pentene (CH3-CH=CH-CH2-CH3), C2 bears -H and -CH3, while C3 bears -H and -CH2CH3, satisfying the condition to form cis and trans isomers.
8What organic compound is the sole product of the vigorous oxidation of symmetrical 2-butene with hot acidic potassium permanganate (KMnO4 / H2SO4)?
A.Ethanoic acid (Acetic acid)
B.Propanone (Acetone)
C.Methanoic acid (Formic acid)
D.Butanoic acid
Explanation: Vigorous oxidation with KMnO4 in H2SO4 cleaves the carbon-carbon double bond completely. A =CH-R group is oxidatively cleaved into a carboxylic acid group (-COOH). Because 2-butene (CH3-CH=CH-CH3) is symmetrical with two =CH-CH3 fragments, cleavage yields 2 moles of ethanoic acid (CH3COOH).
9What volume of acetylene is generated by complete hydrolysis of 128 g of calcium carbide (CaC2, 64.0 g/mol)? Treat the gas as ideal at 0 °C and 1 atm, with molar volume 22.4 L/mol.
A.44.8 L
B.22.4 L
C.11.2 L
D.89.6 L
Explanation: The chemical reaction is CaC2 + 2 H2O -> Ca(OH)2 + C2H2. One mole of CaC2 produces one mole of C2H2. The number of moles of CaC2 is n = 128 g / 64.0 g/mol = 2.00 mol. At STP, 1 mole of an ideal gas occupies 22.4 L, so V = 2.00 mol * 22.4 L/mol = 44.8 L.
10In the Kucherov reaction, hydration of acetylene (ethyne) in the presence of mercury(II) sulfate (HgSO4) and sulfuric acid produces an unstable enol that tautomerizes into which stable product?
A.Acetaldehyde (Ethanal)
B.Acetone (Propanone)
C.Ethanol
D.Acetic acid
Explanation: Hydration of ethyne catalyzed by HgSO4 and H2SO4 initially forms vinyl alcohol (CH2=CH-OH). This enol rapidly tautomerizes via keto-enol tautomerism to the thermodynamically favored carbonyl compound, acetaldehyde (CH3-CHO). Acetylene is the only alkyne whose Kucherov hydration gives an aldehyde; all substituted alkynes give ketones.

About the BAC Chemistry Exam

Independent practice for Examenul Național de Bacalaureat, Chimie (Proba E.d). Independent English-language MCQ study adaptation. It is not an official translation, an official-format simulation, or a substitute for Romanian-language reading and writing, full worked solutions, or oral and practical preparation. Romanian is confirmed. Candidates who studied a subject in a minority language may request that language under the methodology; availability depends on the subject and route. Choose the official organic or general/inorganic paper appropriate to your route; this mixed bank does not represent one paper. Write balanced equations and full calculations.

Exam sponsor: Ministerul Educației și Cercetării / Centrul Național pentru Curriculum și Evaluare (CNCE). The requirements and fees below concern the certification or admission exam, separate from our free practice resources.

Assessment

Question count not published by the exam provider

Time Limit

180 minutes (3 hours)

Passing Score

At least 5/10 in every written paper and an overall written mean of at least 6/10, with required competence assessments completed or recognised. The methodology rounds an overall 5.99 to 6.00.

Exam / Certification Fees

First two Bacalaureat presentations are free; later presentations carry an annually set fee. A current later-attempt amount is not confirmed here.

Exam sponsor website

Fees, eligibility, and exam policies can change. Confirm them with the exam sponsor before applying or paying.

Official sources

Our practice resources: topics covered

We aim to reflect publicly available exam outlines and topic information in our study resources. Coverage, format, and difficulty may differ from the actual exam, and we cannot guarantee that every detail is accurate or current. Confirm exam requirements, fees, and policies with the official exam sponsor.

Not officially weighted here

Organic chemistry

Hydrocarbons, functional compounds, biomolecules and polymers.

Not officially weighted here

General and inorganic chemistry

Atomic structure, bonding, solutions, acid-base reactions and electrochemistry.

Not officially weighted here

Chemical calculations

Stoichiometry, concentrations, energetics, purity and yield.

Preparing for the BAC Chemistry Exam

What You Need to Know

  • Passing score: At least 5/10 in every written paper and an overall written mean of at least 6/10, with required competence assessments completed or recognised. The methodology rounds an overall 5.99 to 6.00.
  • Assessment: Question count not published by the exam provider
  • Time limit: 180 minutes (3 hours)
  • Exam / certification fees: First two Bacalaureat presentations are free; later presentations carry an annually set fee. A current later-attempt amount is not confirmed here. Official sources

Using Our Practice Resources

  • Work through all 100 available questions
  • Review every answer and explanation
  • Track weak areas and revisit them
  • Use our AI tutor for tough concepts

BAC Chemistry: Suggested Study Strategy

1Choose the official organic or general/inorganic paper appropriate to your route; this mixed bank does not represent one paper. Write balanced equations and full calculations.
2Use official papers and marking schemes for the applicable profile. Practise writing complete answers under the three-hour limit.
3Use the questions to identify gaps, then explain why each alternative fails without looking at the feedback.

Frequently Asked Questions

Is this the official examination format or an official translation?

Independent English-language MCQ study adaptation. It is not an official translation, an official-format simulation, or a substitute for Romanian-language reading and writing, full worked solutions, or oral and practical preparation.

What else does the full Bacalaureat require?

Other written papers and required competence assessments: Romanian oral communication, mother-tongue oral communication where applicable, a studied foreign language and digital competence. These must be completed or formally recognised. The subject bank does not replace them.

Which paper and language should I prepare for?

Romanian is confirmed. Candidates who studied a subject in a minority language may request that language under the methodology; availability depends on the subject and route. Choose the official organic or general/inorganic paper appropriate to your route; this mixed bank does not represent one paper. Write balanced equations and full calculations.