Chemistry · Class 11

Active learning ideas

Preparation of Dihydrogen (H2)

Let's unlock the power of the universe's most common element! Today, we will explore how we can produce dihydrogen gas, a clean fuel of the future, right here in our lab and on a massive industrial scale.

• CBSE Learning Outcomes
• NCERT Class 11 Chemistry: Unit 9 - Hydrogen

• 20–35 min
• Pairs → Whole Class
• 3 activities

Activity 01

• Experiential Learning
• 20 min · Whole Class

The Classic 'Pop' Test Demonstration

The teacher demonstrates the reaction of granulated zinc with dilute sulphuric acid in a flask, collecting the evolved gas over water. The collected gas is then tested with a burning splint to produce the characteristic 'pop' sound, confirming the presence of hydrogen.

Explain the principle behind the laboratory preparation of dihydrogen from zinc and dilute acid.

Facilitation Tip

Ensure the apparatus is airtight and use a safety screen for the 'pop' test demonstration.

What to look for

An 'exit ticket' activity where students must write down one laboratory method and one commercial method for preparing H2, including the main reactants for each.

• Apply
• Analyze
• Evaluate
• Self-Awareness
• Self-Management
• Social Awareness

Activity 02

• Experiential Learning
• 30 min · Small Groups

DIY Water Electrolysis

In small groups, students build a simple electrolyser using a 9V battery, two graphite pencil leads as electrodes, and a beaker of salt water. They observe bubbles forming at each electrode and can test the collected gases.

Compare the industrial production of dihydrogen by electrolysis of water and from hydrocarbons.

Facilitation Tip

Add a few drops of universal indicator to the water to show the formation of base at the cathode and acid at the anode.

What to look for

A section in the unit test with short answer questions requiring students to write balanced equations and compare the economic and environmental aspects of electrolysis versus steam reforming.

• Apply
• Analyze
• Evaluate
• Self-Awareness
• Self-Management
• Social Awareness

Activity 03

• Experiential Learning
• 35 min · Pairs

Industrial Process Flowchart Challenge

Students work in pairs to create a comparative flowchart for two commercial methods: steam reforming of methane and the Bosch process. The flowchart should highlight reactants, catalysts, temperatures, and by-products for each process.

Analyse the Bosch process for the commercial production of hydrogen.

Facilitation Tip

Provide pre-printed cards with key terms and conditions that students can arrange to build their flowchart.

What to look for

Students use a 'traffic light' system (red, yellow, green) to rate their confidence in explaining each of the preparation methods discussed in class.

• Apply
• Analyze
• Evaluate
• Self-Awareness
• Self-Management
• Social Awareness

A few notes on teaching this unit

Start with the tangible lab demonstration to spark curiosity. Then, use a simple T-chart on the board to compare 'Lab Methods' vs. 'Commercial Methods', focusing on scale, cost, and purity. Use analogies, for example, comparing lab prep to cooking at home and commercial prep to running a large restaurant kitchen, to make the concepts relatable.

By the end of this session, you will be able to describe different ways to make hydrogen gas and explain why a factory might choose a different method than what we use in the classroom.

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Watch Out for These Misconceptions

• Any metal will react with any acid to produce hydrogen gas.

  Only metals that are more reactive than hydrogen (placed above it in the electrochemical series) can displace it from dilute non-oxidising acids like HCl and H2SO4. Less reactive metals like copper, silver, and gold will not produce hydrogen.

• Hydrogen is readily available in the air for us to collect.

  Although hydrogen is the most abundant element in the universe, it is extremely light and rare in its free gaseous form in Earth's atmosphere. It is almost always found in compounds like water (H2O) and hydrocarbons, from which it must be extracted.

• Electrolysis of water is the main way hydrogen is produced commercially because it is so clean.

  While electrolysis produces very pure hydrogen, it is an energy-intensive and expensive process. Currently, over 95% of commercial hydrogen is produced by steam reforming of natural gas, which is more economical but produces carbon dioxide as a by-product.

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Methods used in this brief

• Experiential Learning