IChO Problems and Solutions

2026

Uzbekistan

A journey through time: The secrets of Avicenna

Problem Solution

Kinetics of the Belousov-Zhabotinsky reaction

Problem Solution

Into Reticular Chemistry

Problem Solution

The nuclear past of Uzbekistan

Cardiolipins

Carbon Nanorings

Nitrogen Fixation

Recycling of Carbon Dioxide

Problem Solution

Cyclodextrin Chemistry

Problem Solution

Practical 1: Synthesise and analyse (A new complex problem)

Problem Solution

Practical 2: Atlas of Enzymes

Problem Solution

Practical 3: The Adventures of Hodja Nasreddin

Problem Solution

2025

United Arab Emirates

Isocaryophyllene, clovene, and humulene

Problem Solution

Rapamycin - A molecular glue

Problem Solution

Lanterns and the Burj Khalifa

Problem Solution

The life of tennis balls

Problem Solution

Solar-powered multi-stage flash desalination

Problem Solution

Solar energy conversion by CO2 reduction

Problem Solution

Dubai crude oil

Problem Solution

Carbon monoxide: Deadly poison or promising therapeutic agent?

Problem Solution

Enzymes and cofactors

Problem Solution

Practical 1: A complex problem

Problem Solution

Practical 2: Exploring the AminOasis

Problem Solution

Practical 3: Rf you ready to spot the answers?

Problem Solution

2024

Saudi Arabia

Ammonia

Electronic nose

Tyrosinase

Potassium

Unknown

Penicillin

Sabic

Safflower

Porphyrin complexes

Practical 1: Indicators

Problem Solution

Practical 2: Titration on a balance

Problem Solution

2023

Switzerland

Molecular Imaging

Problem Solution

Electrochemical CO2 Reduction

Problem Solution

Artificial Photosynthesis

Problem Solution

Fluorinated and Hypervalent Compounds

Problem Solution

Hydrodesulfurization

Problem Solution

Direct Conversion of Methane to Methanol

Problem Solution

Enzyme Kinetics

Problem Solution

Nazarov Reaction

Problem Solution

Electrolysis in Organic Synthesis

Problem Solution

Switzerland - The Country of Pharmaceuticals

Problem Solution

Practical 1: Organic Synthesis: Bleach, a Chameleonic Reagent

Problem Solution

Practical 2: Titration Tango

Problem Solution

Practical 3: Beauty in Simplicity

Problem Solution

2022

China

Rapid and Visual Nucleic Acid Testing for COVID-19

Problem Solution

Chromium in Ancient and Modern Times

Problem Solution

Capture and Transformation of Carbon Dioxide

Problem Solution

A New Journey for Ancient Sulfur

Problem Solution

Interconversion among Nitrogen Oxides

Problem Solution

Enabling Phosphines

Problem Solution

Organic Molecules in Life

Problem Solution

Amazing Chiral Spiro Catalyst

Problem Solution

Total Synthesis of Capitulactone

Problem Solution

2021

Japan

Hydrogen at a Metal Surface

Problem Solution

Isotope Time Capsule

Problem Solution

Lambert-Beer Law?

Problem Solution

The Redox Chemistry of Zinc

Problem Solution

Mysterious Silicon

Problem Solution

The Solid-State Chemistry of Transition Metals

Problem Solution

Playing with Non-benzenoid Aromaticity

Problem Solution

Dynamic Organic Molecules and Their Chirality

Problem Solution

Likes and Dislikes of Capsule

Problem Solution

2020

Turkey

Two Beauties of Turkey: The Van Cat and the Ankara Cat

Problem Solution

A Tale of a Reactive Intermediate

Problem Solution

(±)-Coerulescine

Problem Solution

Symmetry Does Matter!

Problem Solution

Konya, Carrot, Beta-Carotene, Vitamin-A, Immune System, Vision

Problem Solution

Thermodynamics through an Interstellar Journey

Problem Solution

Phthalocyanines

Problem Solution

Boron Compounds and Hydrogen Storage

Problem Solution

Quantification of Heavy Metal Ions

Problem Solution

2019

France

Infinite well and butadiene

Problem Solution

Hydrogen production by water-splitting

Problem Solution

About silver chloride

Problem Solution

From black powder to the discovery of iodine

Problem Solution

Complexes for the formation of nanomachines

Problem Solution

Characterization of a block-copolymer

Problem Solution

Ring motion in a [2]catenane

Problem Solution

Identification and synthesis of inositols

Problem Solution

Synthesis of levobupivacaine

Problem Solution

Practical 1: Greening the oxidation of nitrobenzaldehyde

Problem Solution

Practical 2: The iron age of wine

Problem Solution

Practical 3: Wine for keeping

Problem Solution

2018

Slovakia & Czech Republic

DNA

Problem Solution

Repatriation of remains in the middle ages

Problem Solution

Emerging electro-mobility

Problem Solution

Column chromatography of radioactive copper

Bohemian garnet

Let’s go mushrooming

Cidofovir

Caryophyllene

Practical 1: Haloform reaction with bleach

Problem Solution

Practical 2: A glowing clock reaction

Problem Solution

Practical 3: Mineral water identification

Problem Solution

2017

Thailand

Production of propene using heterogeneous catalysts

Problem Solution

Kinetic isotope effect (KIE) and zero-point vibrational energy (ZPE)

Problem Solution

Thermodynamics of chemical reactions

Problem Solution

Electrochemistry

Problem Solution

Phosphate and silicate in soil

Problem Solution

Iron

Problem Solution

Chemical Structure Puzzles

Problem Solution

Silica Surface

Problem Solution

Into the Unknown

Problem Solution

Total Synthesis of Alkaloids

Problem Solution

Twist & Chirality

Problem Solution

Practical 1A: Acid-base indicator and its application for pH measurement

Problem Solution

Practical 1B: Calcium iodate

Problem Solution

Practical 2: Elaborating Carbon Framework

Problem Solution

2016

Georgia

Problem 1

Problem 2

Problem 3

Problem 4

Problem 5

Problem 6

Problem 7

Problem 8

Practical 1

Practical 2: Determination of fluoride and chloride content in mineral water

Problem Solution

Practical 3: Identifying flavors and fragrances

Problem Solution

2015

Azerbaijan

New and well-forgotten old refrigerants

Problem

Coupling of chemical reactions

Problem

Two binding centers – competition or cooperation?

Problem

From one yellow powder to another: A simple inorganic riddle

Problem

Indispensable glucose

Problem

Bread is the stuff of life

Problem

Not by bread alone

Problem

Oil for Life and Life after Oil

Problem

Practical 1: Tuning bromination selectivity by catalysis

Problem

Practical 2: Analysis of the solution of a chromium – vanadium alloy

Problem

Practical 3: Kinetic determination of Diclofenac (DCF)

Problem