NCEA 91165: organic compounds (Level 2 Chemistry)

What NCEA 91165 assesses

NZQA limits the compounds in the standard (version 2) to alkanes, alkenes, alkynes, haloalkanes, primary amines, alcohols and carboxylic acids, with no more than eight carbons in the longest chain. The properties and reactions are limited to:

• constitutional and geometric (cis and trans) isomers
• classifying alcohols and haloalkanes as primary, secondary or tertiary
• solubility, melting and boiling points
• addition reactions of alkenes, including major and minor products with asymmetric alkenes, and polymerisation
• substitution reactions of alkanes, alcohols and haloalkanes
• oxidation of primary alcohols and of alkenes
• elimination of water from alcohols and of hydrogen halides from haloalkanes, including major and minor products
• acid-base reactions of carboxylic acids and amines

The three grades go up in steps. Achieved names and draws structural formulae of selected organic compounds and gives an account of their chemical and physical properties. Merit makes and explains links between structure, functional groups and chemical properties. Excellence elaborates, justifies, relates, evaluates, compares and contrasts, or uses those links. Every grade needs correct chemistry vocabulary, symbols and conventions, and Excellence needs them used consistently.

The NCEA 91165 exam in 2026 and 2027

NCEA 91165 is one of three Level 2 Chemistry externals, with 91164 (bonding) and 91166 (chemical reactivity). The 2026 exam is on Monday 16 November, in the afternoon session. NZQA's specifications for both years say the exam is on printed paper and 91165 is a 4-credit external.

• Three questions: you answer all three, and each has several parts. Questions may be set in contexts that are unfamiliar to you, and any context-specific formulae are given in the exam.
• Calculator: an approved scientific or graphics calculator is required.
• Resource booklet: it has the formulae you need, such as n = cV, and a periodic table with element symbols, atomic numbers and molar masses. Use the molar masses given with the question or on the periodic table.
• Calculations: show all working, round numerical answers to three significant figures and include the correct units.
• Conventions: symbols, nomenclature, spelling and formatting follow IUPAC conventions. The reference sheet for these is not provided in the exam.
• Physical properties: NZQA says solubility, melting and boiling points mean you need to understand how carbon-chain length and functional groups affect them. An explanation of the chemistry of how they do so is not required.

How NCEA 91165 is marked

Three questions, each scored N0 to E8, make a total out of 24. Organic questions reward accuracy in drawing before anything else: NZQA's report says a bond drawn to the wrong atom or an "isomer" that is the same molecule flipped over was a typical Not Achieved error.

NCEA 91165 cut scores

Boundaries were 7 and 14 for Achieved and Merit in 2022 and 2023, and Achieved was 8 in the other years. Merit rose to 15 in 2021. The scores are where each grade begins, out of 24.

Cut scores 2025

2025 schedule: Achieved from 8, Merit from 14, Excellence from 19. The same as 2024.

Cut scores 2024

2024 schedule: Achieved from 8, Merit from 14, Excellence from 19. Compared with 2023, Achieved went up by 1.

Cut scores 2023

2023 schedule: Achieved from 7, Merit from 14, Excellence from 19. The same as 2022.

Cut scores 2022

2022 schedule: Achieved from 7, Merit from 14, Excellence from 19. Compared with 2021, Achieved came down by 1 and Merit came down by 1.

Cut scores 2021

2021 schedule: Achieved from 8, Merit from 15, Excellence from 19.

Worked examples at each grade

Achieved: naming and classifying isomers

Draw and name the four constitutional isomers of C₄H₉Br and classify each as primary, secondary or tertiary. Classify by the number of carbon atoms attached to the carbon that holds the bromine:

• 1-bromobutane, CH₃CH₂CH₂CH₂Br: primary
• 2-bromobutane, CH₃CHBrCH₂CH₃: secondary
• 1-bromo-2-methylpropane, (CH₃)₂CHCH₂Br: primary
• 2-bromo-2-methylpropane, (CH₃)₃CBr: tertiary

NZQA's 2025 report says candidates who drew "isomers" that were the same molecule flipped over did not gain credit. Check that each structure really has a different connection of atoms.

Merit: major and minor products

Propene reacts with HBr. In the addition, the hydrogen adds to the carbon that already has more hydrogens, so the major product is 2-bromopropane, CH₃CHBrCH₃, and the minor product is 1-bromopropane. Now 2-bromobutane is heated with potassium hydroxide in ethanol, an elimination. Two alkenes can form: but-2-ene, which loses the hydrogen from the carbon with fewer hydrogens, is the major product, and but-1-ene is the minor product. The report says Merit candidates used this rule (Zaitsev's rule) and linked the asymmetric reactant to two different products.

For geometric isomers, but-2-ene has cis and trans forms but but-1-ene does not. The C=C double bond stops rotation, and each carbon of the double bond needs two different groups. But-1-ene has two hydrogens on one carbon of the double bond, so no cis/trans pair.

Excellence: a reaction scheme with conditions and observations

Show how propan-1-ol can be converted to propan-2-ol, and how butan-1-ol can be turned into a carboxylic acid and tested.

1. Propan-1-ol is heated with concentrated H₂SO₄: elimination of water gives propene.
2. Propene reacts with HBr: addition gives 2-bromopropane as the major product.
3. 2-bromopropane is warmed with aqueous KOH: substitution gives propan-2-ol.

For the acid, butan-1-ol is heated with acidified permanganate, MnO₄⁻/H⁺, or acidified dichromate, Cr₂O₇²⁻/H⁺, which oxidises the primary alcohol to butanoic acid. With permanganate the purple colour goes colourless; with dichromate orange turns green. To test for the acid, add a carbonate: it fizzes as CO₂ forms. Excellence candidates in 2025 combined the reaction type, the observations, the conditions (such as heat) and the structural change in one clear paragraph, and referred to the actual molecules in the question.

Now try naming organic families in our Organic Chemistry course, then press Mark to check your answer in the course:

Exam answers

The answers and a worked mark scheme come with today's paper once it is marked. We do not publish official or past paper answers. Every question on the daily paper is our own.

Use the daily paper as a practice exam

The Level 2 Chemistry track above is a short timed mock of 8 questions, not a full exam and not written by NZQA (NCEA Level 2 Chemistry). It covers alkanes, alkenes and halogenoalkanes, alcohols, and isomerism and nomenclature, which support 91165. It uses UK-style names such as "halogenoalkane" for the same compounds, and it also includes redox, kinetics and periodicity, which are not part of 91165, so treat those as extra. For the whole course, see the NCEA Level 2 Chemistry guide.

Is NCEA 91165 changing?

The 2027 specification keeps this standard and its note on solubility, melting and boiling points. Level 3 Chemistry then assumes it, so the standard feeds straight into 91391.

Common mistakes in NCEA 91165

• Bonding to the wrong atom. NZQA's 2025 report gives drawing C-HO instead of C-OH as an example.
• Confusing elimination with substitution or addition. The products differ, so name the reaction type first.
• Drawing the same molecule twice. Flipped or rotated structures are not new isomers.
• Vague observations. "It changes colour" earns nothing: give the start and end colours, and say what the litmus paper started as.
• Double bonds in a polymer chain. The polymer has a single-bonded backbone, and the monomer has the double bond.
• Generic textbook answers. Refer to the specific molecules in the question.

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