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Leaving Cert Chemistry: Mandatory experiments

How often Mandatory experiments comes up on the Chemistry papers, every year it was asked, and questions to try.

HL Asked on 10 of the last 10 Higher Level papers, most recently in 2026. banker

OL Asked on 10 of the last 10 Ordinary Level papers, most recently in 2026. banker

June 2027 is the first exam on the new Chemistry course. These come from the 2016–2026 papers, so read them as a guide.

Mandatory experiments, Higher Level(7 marks)

Quick ones on Mandatory experiments.

(a)Primary standard used to standardise a hydrochloric acid solution?
  1. Sodium hydroxide pellets (dried)
  2. Anhydrous sodium carbonate
  3. Pure ethanoic acid
(b)Flame colour given by a sodium compound in a flame test?
  1. Green
  2. Lilac
  3. Yellow
(c)Flame colour given by a potassium compound in a flame test?
  1. Lilac
  2. Crimson
  3. Yellow
Show the answers

(a) Anhydrous sodium carbonate

(b) Yellow

(c) Lilac

Your turn: Higher Level questions on Mandatory experiments.

Higher Level

Asked on 10 of the last 10 Higher Level papers, most recently in 2026. banker

Every paper, year by year

YearWhere it came up
2026Q1, Q2, Q3
2025Q1, Q2, Q3, Q11(b)
2024Q1, Q2, Q3, Q4(b)
2023Q1, Q2, Q3
2022Q1, Q2, Q3, Q4(d), Q4(g)
2021Q1, Q2, Q3
2019Q1, Q2, Q3
2018Q1, Q2, Q3
2017Q1, Q2, Q3, Q10(a)
2016Q1, Q2, Q3, Q4(h)

Links open the State Examinations Commission’s paper for that year.

More Mandatory experiments questions

Mandatory experiments, 3 marks

Why must a burette be rinsed with the solution it will hold rather than with water?

  1. Water reacts with the indicator in the flask and changes its colour early
  2. Rinsing with the solution removes any air bubbles from the tip
  3. Water left inside would dilute the solution and change its concentration
Show the answer

Water left inside would dilute the solution and change its concentration

The concentration of what comes out of the burette matters, so any leftover water would make the titre wrong.

Mandatory experiments, 2 marks

In the brown ring test, which solution is added before the concentrated sulfuric acid?

  1. Silver nitrate solution
  2. Freshly made iron(II) sulfate
  3. Barium chloride solution
Show the answer

Freshly made iron(II) sulfate

Iron(II) sulfate is mixed with the test solution first. Concentrated sulfuric acid then forms a layer underneath, and a brown ring at the join shows nitrate.

Mandatory experiments, 2 marks

Flame colour given by a copper(II) salt?

  1. Blue-green
  2. Lilac
  3. Crimson
Show the answer

Blue-green

Copper gives a blue-green flame. Lilac is potassium and crimson is lithium or strontium.

Ordinary Level

Asked on 10 of the last 10 Ordinary Level papers, most recently in 2026. banker

Every paper, year by year

YearWhere it came up
2026Q1, Q2, Q3, Q11(a)
2025Q1, Q2, Q3, Q4(a)
2024Q1, Q2, Q3
2023Q1, Q2, Q3
2022Q1, Q2, Q3, Q4(f), Q9
2021Q1, Q2, Q3, Q4(c)
2019Q1, Q2, Q3
2018Q1, Q2, Q3, Q9
2017Q1, Q2, Q3, Q7, Q9
2016Q1, Q2, Q3, Q10(a)

Links open the State Examinations Commission’s paper for that year.

More Mandatory experiments questions

Mandatory experiments, 2 marks

Flame test colour given by a lithium compound?

  1. Lilac
  2. Apple green
  3. Crimson red
Show the answer

Crimson red

Lithium gives a crimson red flame. Potassium gives lilac and barium gives a pale green flame.

Mandatory experiments, 2 marks

Result of adding barium chloride solution to a solution containing sulfate ions?

  1. A brown ring where the two layers meet
  2. A white precipitate that does not dissolve in dilute HCl
  3. A yellow precipitate that dissolves in dilute HCl
Show the answer

A white precipitate that does not dissolve in dilute HCl

Barium sulfate is a white solid. It stays undissolved when dilute hydrochloric acid is added, which rules out sulfite.

Mandatory experiments, 2 marks

Solvent used to recrystallise impure benzoic acid in the school experiment?

  1. Hot water
  2. Cold water
  3. Dilute hydrochloric acid
Show the answer

Hot water

Benzoic acid dissolves well in hot water but poorly in cold water, so pure crystals form as the solution cools.

Other Chemistry topics

All of Leaving Cert Chemistry