Toxicity of different chemicals

Again, I'm writing this one to create awareness among students and those who are working in the chemistry lab. Sadly, they do not know seriousness of using some toxic chemicals and its health effects. I hope this post is very useful for them and they can know how to handle these toxic chemicals. The below list will tell you what you should do and what should not:


1.   Lithium and its compounds: Lithium metal should be handled carefully as it reacts with water violently. In case of lithium compounds, it is wise to avoid them as they affect the central nervous system.

2. Fluorine and Fluorides: Fluorine is the most reactive element known. It reacts with most of the elements violently. Even chemists do afraid to handle Fluorine. So, It should be handled with utmost care. Fluorides will release very toxic and corrosive hydrogen fluoride on adding concentrated sulphuric acid.

3. Sodium and its compounds: Elemental sodium possess fire hazard as it reacts with water almost explosively. So, extreme care should be taken while handling Sodium metal. Most of the sodium compounds are safe to use. But, there are some exceptions - Sodium cyanide, Sodium azide, Sodium chromate etc.. Here you see the toxicity mainly depends upon the anions present in it.

Sodium metal under paraffin oil

4. Magnesium and its compounds: Magnesium possess fire hazard as it burns in the oxygen violently. It is hard to distinguish magnesium fire. Also, it produces harmful ultraviolet rays when burning. But, it won't be a problem if you handle it carefully. Magnesium compounds are safe to use.

Magnesium ribbon

Anhydrous aluminium chloride

5. Aluminium and its compounds: Do not possess significant health hazard. But, you should know the reactivity of Aluminium before you use it as it reacts with some elements violently. For example: Bromine, Chlorine etc....

6. Phosphorus and its compounds: We all know white phosphorus possess significant fire and health hazard. It should be kept under the water since it reacts with atmospheric oxygen violently and produces clouds of phosphorus pentoxide. As far as red phosphorus is concerned, it is lot safer to use compare to white phosphorus. It is not pyrophoric  like white phosphorus. Oxides of phosphorus and phosphine should be avoided as they will affect our health significantly.

7. Sulphur and its compounds: Elemental sulphur is not toxic. But, it possess fire hazard when it mixes with strong oxidizing agents like potassium chlorate. Sulfur compounds are toxic especially those are in gaseous phase. For example: Hydrogen sulphide, sulfur dioxide etc....

 

Elemental sulphur

8..Chlorine: Chlorine is highly toxic and it will cause serious damage to our lungs even if you inhaled for few minutes.

9. Potassium and its compounds: Again, Potassium possess significant fire hazard as it reacts with water explosively. It should be handled under expert supervision. Like sodium compounds, the toxicity mainly depends upon the anions present in it. Otherwise, they are safer to use.

10. Calcium and its compounds: Albeit, Calcium metal does not react with water violently like alkali metals, care should be taken. Calcium compounds are pretty benign and safer to use.

11. Chromium compounds: Chromium compounds are extremely toxic. Especially, hexavalent chromium compounds are carcinogenic (will cause cancer) on chronic exposure. Also, they are strong oxidizing agents. They react violently with strong reducing agents. Sadly, some will cause reproductive defects. Eg. Potassium chromate. They are also very dangerous for the environment. But, people love chromium compounds as they are very colorful.

12. Manganese compounds: Not possessing significant health hazard. Anyway, chronic exposure should be avoided.

Manganous sulphate

13. Iron compounds: Safe to use.

Ferrous oxalate

14. Cobalt compounds: Dangerous for the environment and extremely toxic. An animal carcinogen.

15. Nickel compounds: Dangerous for the environment and extremely toxic. Chronic exposure will cause cancer. May cause allergic reaction to the skin on contact.

16. Copper compounds: Toxic but manageable.

17.Zinc compounds: Toxic but manageable.

18. Arsenic and its compounds. Extremely dangerous for the environment and will cause cancer even on few exposure. Significant health hazard and will lead you to death.

19. Bromine and bromides: Bromine is highly toxic and will cause damage to our respiratory system. Also, it is very corrosive and will cause burns. It will react violently with some metals.

Bromine in sealed ampules

Bromides will release toxic bromine and hydrogen bromide on adding concentarted sulphuric acid.

Strong bromine water

20. Silver compounds: Not possess serious health hazard.

21. Cadmium compounds: Extremely dangerous for the environment and will cause cancer even on few exposure. Significant health hazard and will lead you to death.


22. Tin compounds: Moderately toxic but manageable.

 

Stannous chloride

23. Antimony compounds: Dangerous for the environment and extremely toxic.

24. Iodine and Iodides: Toxic on ingestion. Do not inhale iodine vapor much. Overall toxicity is less compare to bromine and chlorine. Again, Iodides will release a mixture of Iodine & Hydrogen Iodide on adding concentrated sulphuric acid.

Iodine

25. Barium compounds: All are extremely toxic except Barium sulphate since it is completely insoluble in water. Barium compounds will cause lung disease and other serious concerns. If a person suffering from Barium poisoning, it is wise to give sodium or magnesium sulphate solution to the victim. Once the victim drink that solution, non toxic barium sulphate is precipitated and it will be eliminated completely from the body.

Barium sulphate

26. Mercury and its compounds: Cumulative poison. Mercury and its compounds are extremely toxic. Hence, they should not be released to the environment.

27. Lead and its compounds: Extremely toxic and possess serious health risks. Cumulative poison. Lead compounds will target almost all the organs in our body and will lead to death on chronic exposure. As there are many risks involved with lead compounds, they should not be released to the environment.

28. Ammonia and its compounds: Ammonia is moderately toxic. It will be fatal after a few deep breaths of the gas. Its compounds have a  low to moderate level of toxicity. Not a serious health concern in overall picture.

I always believe it is wise to avoid compounds which possess extreme health hazard and also dangerous for the environment as we do not have proper disposal facilities and need of very good lab facilities. Also, these will affect our health significantly even on inhalation. But, we cannot deny the fact that every chemical has tonnes of uses albeit some are very toxic.

You can write your comments on my post and I will help you if I can :)

5 Easy steps to identify a compound
                       

I'm writing this post to help students who are getting ready for chemistry exams. When I was doing my higher secondary, some students were not able to identify a compound and found it very tough. But, I can help you in finding a compound only in few steps. You need not to do all steps that you see in the chemistry manual.
Just follow my simple steps and they will guide you through.

First, we are going to take concentrated sulphuric acid (king of chemicals) which will confirm the anion straightaway.

1. Brisk effervescence - Carbonate
2. Rotten egg smell - Sulphide
3. Dense pungent smelling gas (Hydrogen chloride) - Chloride
4. Pungent smelling gas evolves (Nitric acid vapor) and it liberates reddish brown gas (Nitrogen dioxide) on adding Magnesium or Copper turnings. - Nitrate
5. Dark red gas resembles the smell of chlorine to an extent - Bromide
6. Purple vapor - Iodide
7. Pungent smelling gas decolorizing potassium permanganate solution (sulphur dioxide)  - Sulfite
8. Reddish brown gas turns ferrous sulphate paper black - Nitrite

(Caution: Add only few drops of concentrated sulphuric acid to the salt as it reacts with most of the compounds vigorously and will produce toxic gases enormously  in some cases. Also, do not pour water in the concentrated sulphuric acid directly as it has great affinity towards water and the reaction may spit out the acid and also will generate lot of heat. To dilute the sulphuric acid, add the acid slowly through the side of the beaker containing water)


May be we are not allowed to use metal turnings in the school lab. In that case, please add few drops of concentrated hydrochloric acid and heat the mixture (Hcl+salt) gently. If reddish brown gas evolves - Nitrate is confirmed. Please do not heat it strongly as the reaction may spits out the acid.

If none of these happen, It must be sulphate (salt of sulphuric acid). Because, sulphate ions always do form a strong bond with cations and they cannot be decomposed easily by most of the reagents. In that case, add Barium chloride solution and it will give white precipitate (Barium sulphate) - Sulphate is confirmed.

If we find the anion correctly, we are not far away from the success as we have been already provided with the list of salts that we are going to use in exam practicals. For example, if the anion is nitrate, then we can come to the conclusion, it must be one of the nitrates that we are using for practicals. We had used only 2 nitrates i.e. Copper nitrate & Lead nitrate. Copper salts can be identified by its color. So, it is enough to do the test for Lead.

Next, we are going to find the cation. Before that, let's do the flame test which will help you in finding the presence of two cations, Barium & Calcium.

Barium - Green flame
Calcium - Brick red
Strontium & Lithium  - Crimson


If the above flame test is not successful, then add sodium hydroxide to the salt and test the result with the following:

1. White precipitate - Aluminium, Magnesium & Zinc (White precipitate will lead you for the confirmatory test for these three)

If white precipitate not appears, heat the mixture. Pungent smelling gas confirms the presence of ammonium ion.

2. Hydrogen sulphide test: This test can be used to determine the presence of heavy metals as they do precipitate out the colorful sulphides.On passing the hydrogen sulphide through salt solution, the characteristic colors show the presence of the below cations:

1. Copper, Nickel, Lead, Silver & Cobalt - Black (In excess, it will also precipitate out the metal on the surface)
2. Chocolate brown - Bismuth, Stannous, Manganese.
3. Yellow to Orange - Cadmium or Antimony

 You can distinguish the salts of these metals by noticing the color.

1. Copper - Most of the copper compounds are blue in color. There are some exception though. Ex: Copper chloride is green.
2. Nickel - Most of the copper compounds are green in color.
3. Cobalt - Rosy red, blue
4.Tin, Lead & Bismuth - Mostly colorless

Then, you can do the confirmatory test for these metals if needed.

You can find the anion in a single step and for cation, you will not need more than 3 or 4 steps. Hence, you can find a compound no more than 5 steps or may be less.


You can also identify other ions by these steps. As I'm not sure if there is any new ion added in your practicals (new syllabus), I just write these based on the compounds that we used for our practicals.
 
I hope this is very helpful for your exams. If you have any questions, you can post them below and I will explain you in detail.

My edits in wiki

Hydride (Last 2 lines in Nomenclature paragraph)


A notable thing is that all solid non-metallic & metalloid hydrides are highly flammable. But,when Hydrogen combines with halogens, it produces acids rather than hydrides and they are not flammable.

Zinc nitrate 

Zinc nitrate is a highly deliquescent substance which is usually prepared by dissolving zinc in nitric acid. It can be used as a mordant in dyeing. Zinc nitrate is soluble in both water and alcohol.

Sulphur trioxide

Safety

Sulfur trioxide will cause serious burns on both inhalation and ingestion since it is highly corrosive and hygroscopic in nature. SO3 should be handled with extreme care as it reacts with water violently and produces highly corrosive sulfuric acid.