Hoffman Voltameter
Product Code : EL-EAE-10294
Quick answer: The Hofmann voltameter is a glass apparatus for the electrolysis of water, showing that water gives two volumes of hydrogen for every one volume of oxygen. Its two limbs are each graduated 50 x 0.2 ml, with stopcocks, removable carbon electrodes, a connecting tube and a funnel-shaped reservoir bulb. Lab Exports manufactures it in Delhi for schools, colleges and universities.
Specifications
| Component | Specification |
|---|---|
| Construction | Glass, two connected limbs |
| Graduation | Each limb 50 x 0.2 ml |
| Electrodes | Removable carbon electrodes |
| Fittings | Stopcocks and connecting tube |
| Reservoir | Funnel-shaped reservoir bulb |
How the electrolysis experiment is done
Pure water conducts very poorly, so a little dilute sulphuric acid is added as the electrolyte. When a direct current is passed, hydrogen is released at the cathode (negative electrode) and oxygen at the anode (positive electrode): 2H2O -> 2H2 + O2. The gases collect at the top of the two graduated limbs, and the volume of hydrogen is twice the volume of oxygen, matching the formula H2O.
- Open the stopcocks and fill the apparatus through the reservoir bulb with acidified water until both limbs are full, then close the stopcocks.
- Connect the carbon electrodes to a DC supply, noting which limb is joined to the negative terminal.
- Switch on and watch bubbles rise from both electrodes into the graduated limbs.
- After a few minutes switch off and read the gas volume in each limb against the 0.2 ml graduations.
- Test the gases: hydrogen burns with a squeaky pop, and oxygen relights a glowing splint.
A ratio slightly different from exactly 2:1 is normal at the start, because oxygen is a little more soluble in water than hydrogen; the ratio comes closer to 2:1 as the run continues.
Key features
- Two connected glass limbs, each graduated 50 x 0.2 ml, for reading gas volumes directly.
- Removable carbon electrodes that can be taken out for cleaning or replacement.
- Stopcocks for releasing and testing the collected gases.
- Funnel-shaped reservoir bulb and connecting tube for filling the apparatus with electrolyte.
- Shows the 2:1 volume ratio of hydrogen to oxygen from the electrolysis of water.
Documentation and supply
Most Lab Exports products carry a one-year manufacturer warranty.
Lab Exports manufactures the Hofmann voltameter at its works in Laxmi Nagar, Delhi, and supplies it to schools, colleges and universities in India and 60+ countries, handling the export documents for each shipment. More about the company is on the About Lab Exports page.
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Frequently asked questions
What does the Hofmann voltameter demonstrate?
It shows by electrolysis that water produces two volumes of hydrogen for every one volume of oxygen, confirming the formula H2O.
How are the limbs of the voltameter graduated?
Each of the two limbs is graduated 50 x 0.2 ml, so gas volumes can be read to 0.2 ml.
Which electrolyte is used in a Hofmann voltameter?
Water with a little dilute sulphuric acid is the usual electrolyte, as pure water conducts too poorly for steady electrolysis.
What is the price of the Hofmann voltameter?
Prices are not published on the website. Add the Hofmann voltameter to the Enquiry Cart with the Add To Cart button on this page, or email [email protected] with the house code EL-EAE-10294 and the quantity, to receive a quotation.
Does Lab Exports manufacture the Hofmann voltameter?
Yes. Lab Exports manufactures the Hofmann voltameter at its works at 11/315, Lalita Park, Laxmi Nagar, Delhi 110092, under house code EL-EAE-10294.
Request a quote
Email [email protected] with the house code EL-EAE-10294 and the quantity, or add the Hofmann voltameter to the Enquiry Cart with the Add To Cart button on this page. Tender buyers can also see the Tenders and OEM page.
