Hydroiodic acid (CAS 10034-85-2): storage and disposal
Hydroiodic acid is held as a 57% solution in college and university stores. It causes severe skin burns and eye damage. A bottle of this kind is opened rarely and can stand for a long time, so light, the cap and the neighbours on the shelf decide how it ages. A browning liquid is the typical thing a holder sees and has to describe.
- CAS number
- 10034-85-2
- Form
- Solution
- Storage class
- Acid
- Signal word
- Danger
- Usual EWC code
- 16 05 06*
Corrosive
What to do this week
- Check the label is readable and write down the opened date if it is not already there.
- Check it is stored as acid stock and apart from the items listed under "Do not store with".
- If you no longer need it, add it to your disposal list so it goes on the next collection.
Safe storage in a school or lab
A bottle of 57% hydroiodic acid in a college stockroom is often opened rarely, which leaves it standing long enough for light and air to work on it. Keep it away from windows and bench lighting, low down on an acid-resistant tray in a ventilated corrosive store. Sulfides such as ammonium sulfide solution and iron(II) sulfide release toxic hydrogen sulfide with it, bleach compounds release toxic chlorine, and potassium cyanide releases highly toxic hydrogen cyanide. Chlorates can form explosive chlorine dioxide. Alkalis, solvents and oxidisers each need their own shelf, since acid fumes attack caps and seals.
How to tell it has deteriorated
A brown tint is the first thing to see. Clear liquid turns yellow and then brown as the iodide is oxidised to iodine by air and light, and the change is faster in a bottle that has been opened often or left in a bright room. An old bottle can leave brown marks around the neck where vapour has crept out. Do not try to clear the colour. Also check for crust on the neck, a perished cap, cracked glass and corroded fittings close by. A bottle that has browned is still the same corrosive acid and should be listed for collection, not kept for another term.
How it must be disposed of
By specialist collection only. It never goes down the drain or into general waste. It is normally packed in a corrosive acid laboratory pack with compatible chemicals.
It must never be tipped into a sink or drain, even in small amounts, and a bin or skip is no better. It must not be diluted or neutralised, and the brown colour must not be bleached out. The only route is specialist collection, with the bottle described as an inorganic acid under 16 05 06*. Record the 57% strength, the depth of the tint, the state of the cap and whether there is brown staining on the shelf or tray. Staining and crust make a bottle awkward to lift, so say so when booking. The collector keeps it away from sulfides, bleach compounds, cyanides and chlorates.
| EWC code, laboratory chemicals | 16 05 06* |
|---|---|
| Discarded inorganic chemical, not a laboratory pack | 16 05 07* |
| Hazardous waste | Yes |
The code depends on where the waste came from and what it is mixed with. Use the waste code finder to see why.
Do not store with
- FlammableOxidising acids can ignite flammable materials, and acid fumes attack containers and seals.
- AlkaliAcids and alkalis react with strong heat and spattering if they meet.
- OxidiserMany oxidisers release toxic gas or become unstable in contact with acid.
- ToxicToxic stock is stored apart from acids. Several toxic salts release toxic gas in contact with acid.
Named chemicals to keep apart
- AcetoneOxidising acids can ignite flammable materials, and acid fumes attack containers and seals.
- Ammonia solutionAcids and alkalis react with strong heat and spattering if they meet.
- Ammonium sulfide solutionSulfides release toxic hydrogen sulfide gas with acids.
- Calcium hypochloriteHypochlorites release toxic chlorine gas in contact with acids.
- Chloramine THypochlorites release toxic chlorine gas in contact with acids.
- EthanolOxidising acids can ignite flammable materials, and acid fumes attack containers and seals.
- FormalinToxic stock is stored apart from acids. Several toxic salts release toxic gas in contact with acid.
- HexaneOxidising acids can ignite flammable materials, and acid fumes attack containers and seals.
Show 16 more
- Hydrogen peroxideMany oxidisers release toxic gas or become unstable in contact with acid.
- Iron(II) sulfideSulfides release toxic hydrogen sulfide gas with acids.
- Mercury(II) chlorideToxic stock is stored apart from acids. Several toxic salts release toxic gas in contact with acid.
- MethanolOxidising acids can ignite flammable materials, and acid fumes attack containers and seals.
- Potassium chlorateChlorates and strong acids can form explosive chlorine dioxide.
- Potassium cyanideCyanides release highly toxic hydrogen cyanide gas with acids.
- Potassium ferricyanideHeating or strong acids can release toxic hydrogen cyanide from these complexes.
- Potassium ferrocyanideHeating or strong acids can release toxic hydrogen cyanide from these complexes.
- Potassium hydroxideAcids and alkalis react with strong heat and spattering if they meet.
- Sodium azideAzides release highly toxic and explosive hydrazoic acid with acids.
- Sodium chlorateChlorates and strong acids can form explosive chlorine dioxide.
- Sodium cyanideCyanides release highly toxic hydrogen cyanide gas with acids.
- Sodium dichloroisocyanurateHypochlorites release toxic chlorine gas in contact with acids.
- Sodium hypochloriteHypochlorites release toxic chlorine gas in contact with acids.
- Sodium nitriteNitrites release toxic nitrogen oxides with acids.
- Sodium sulfideSulfides release toxic hydrogen sulfide gas with acids.
Common quantities we collect
Usually held as: 57%.
Part-used bottles and full containers are both fine. Tell us the size and how many, and an estimate is enough for a first price.
Where it is commonly held
Hazard statements
- H314 Causes severe skin burns and eye damage.
Precautionary statements
- P260 Do not breathe dust, fume, gas, mist, vapours or spray.
- P264 Wash hands and exposed skin thoroughly after handling.
- P280 Wear protective gloves, protective clothing, eye protection and face protection.
- P301+P330+P331 IF SWALLOWED: Rinse mouth. Do NOT induce vomiting.
- P302+P361+P354 IF ON SKIN: Take off immediately all contaminated clothing. Immediately rinse with water for several minutes.
- P304+P340 IF INHALED: Remove person to fresh air and keep comfortable for breathing.
- P305+P354+P338 IF IN EYES: Immediately rinse with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.
- P316 Get emergency medical help immediately.
- P321 Specific treatment (see supplemental first aid instruction on this label).
- P363 Wash contaminated clothing before reuse.
- P405 Store locked up.
- P501 Dispose of contents and container in accordance with local, regional, national and international regulations.
- P261 Avoid breathing dust, fume, gas, mist, vapours or spray.
- P264+P265 Wash hands and exposed skin thoroughly after handling. Do not touch eyes.
- P271 Use only outdoors or in a well-ventilated area.
- P317 Get medical help.
- P403+P233 Store in a well-ventilated place. Keep container tightly closed.
- P410+P403 Protect from sunlight. Store in a well-ventilated place.
Substance as classified, dilutions may differ.
Questions
Is a brown bottle of hydroiodic acid dangerous to keep?
The brown tint shows iodide being oxidised by air and light. The liquid remains a corrosive acid classified for severe burns, so handle it as you always would, keep the cap on, check the neck and cap for damage and plan a collection rather than holding it for years.
Where in a college store should it be kept?
Low down on an acid-resistant tray in a ventilated corrosive store, out of direct light. Keep it away from sulfides, hypochlorites, cyanides and chlorates, and keep alkalis on a different shelf from the acid.
Do we need to list a bottle that is nearly empty?
Yes. A nearly empty bottle still holds corrosive acid and a crusted neck, so it needs describing like any other. Leave the cap on, do not rinse it out, and put it on the inventory with the strength and condition.
