Quick Answer: The Kipps gas generating apparatus in clear glass is a three-bulb gas generator that delivers carbon dioxide, hydrogen or hydrogen sulfide on demand from a solid and a dilute acid. It suits school and college practicals where a steady stream of gas is needed at the turn of a tap.
Charging the Apparatus for a Practical
Preparing the generator follows a fixed order. The middle globe is filled through its side opening with lumps of the solid, for example marble chips for carbon dioxide, and the opening is closed with its stopper or outlet fitting. With the tap open, dilute acid is poured into the top reservoir; it runs down the central tube, fills the lowest globe and rises into the middle one until it reaches the solid. Gas production begins at once, and the first gas out, mixed with air, is allowed to escape before collection starts.
From then on, the tap is the only control. Opening it lets gas flow to a delivery tube, gas jar or test tube; closing it pushes the acid away from the solid and production stops. At the end of the session, the spent acid is run off through the outlet near the base, the solid is rinsed and removed, and the globes are washed.
The title names clear glass without giving the composition, which in catalogue terms usually means soda-lime rather than borosilicate. Because the apparatus is never heated, that difference mainly affects durability. The borosilicate glass version is the sturdier option for heavy use, and a gas jar with ground flange is the usual vessel for collecting the gas.
Specifications
| Item | Three-globe gas generator with outlet tap |
| Material | Clear glass, type unspecified |
| Reaction type | Solid lumps with dilute acid at room temperature |
| Control | Outlet tap; closing it separates acid from solid |
| Capacity | Confirm at enquiry |
Applications
- Filling gas jars with carbon dioxide to show that it is denser than air and puts out a burning splint
- Bubbling carbon dioxide through limewater to show the milky calcium carbonate precipitate
- Collecting hydrogen over water for density and burning tests, discarding the first portions
- Supplying hydrogen sulfide for salt analysis at senior secondary level, in a fume cupboard
Care & Handling
- Use dilute acid only and keep the tap closed while the apparatus stands charged.
- Stand the generator on a flat, stable bench, since the charged apparatus is heavy and top-heavy.
- Replace the solid when gas flow stays weak even with fresh acid, as the lumps become coated with reaction products.
- Keep flames away from the outlet while hydrogen is being produced.
Why Choose LabEquip
Schools and junior colleges that prepare gases in front of a class or for group work often choose a clear glass Kipps gas generating apparatus as the everyday option. It is part of the LabEquip chemistry lab equipment range; ask about class-set quantities through the contact page.
Frequently Asked Questions
How much acid should be poured in?
Enough to reach the solid in the middle globe with the tap open, but not so much that the top reservoir overflows when the tap is closed and the acid is pushed back up. Leave room in the reservoir for the displaced acid.
Why should the first gas be discarded?
The globes start full of air, which mixes with the first gas produced. Letting this out before collecting gives a purer sample, and for hydrogen it removes an air mixture that could explode if lit.
What acid is used for carbon dioxide?
Dilute hydrochloric acid with marble chips. Dilute sulfuric acid is avoided because it forms calcium sulfate, which is only slightly soluble and coats the marble, slowing and then stopping the reaction.
Why has the gas flow become slow?
The acid may be exhausted, or the solid may be used up or coated. Drain the acid and replace it with fresh dilute acid; if the flow is still weak, recharge the middle globe with new lumps.
Can the clear glass version be used for hydrogen sulfide?
Yes, the chemistry is the same, but the gas is toxic, so the whole apparatus should stand in a fume cupboard during use and be drained and rinsed there afterwards.
How should the apparatus be stored between practicals?
Drain it completely, rinse out all acid and solid residues, and store it dry with the stopcock and stoppers loosened so they cannot seize. Acid left standing in it for weeks encourages leaks and stuck joints.
Last Updated: September 2026
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