As you said, one cannot add HCl to destroy carbonates in a sample which is to be tested for halide ions. Dilute nitric is the only choice, because you would not use sulfuric acid in the case of halides because (i) your test sample may contain ions which will precipitate with sulfate (Ba, Ag, Pb, Ca etc.).
Why can’t we use nitric acid instead of dilute sulfuric acid?
Sulfuric acid cannot be substituted for nitric acid because aqua regia requires a strong oxidant, and sulfuric acid is not one; but sodium nitrate can often be used as a substitute for nitric acid.
Is hydrochloric acid stronger than nitric acid?
Yes, hydrochloric acid is stronger than nitric acid. This is due to the deprotonation of hydrochloric acid in aqueous form. This makes hydrochloric acid stronger than nitric acid.
Why diluted hydrochloric acid Cannot be used in the halide test?
The acid reacts with any carbonate ions present. This removes them, so stopping them giving an incorrect positive result for chloride ions. Explain why, in a test for halide ions, dilute hydrochloric acid cannot be used to acidify the sample.
Why must dilute nitric acid be added?
The nitric acid is added first to remove any carbonate ions that might be present – they would produce a white precipitate of silver carbonate, giving a false positive result for chloride ions.
Why is nitric acid used instead of sulfuric acid or hydrochloric acid?
HNO3 ( Nitric Acid ) is consider as a Stronger Acid based on its pKa. In the other hand Sulfuric acid (HSO4) is a Medium Acid based on its strength. If you want a faster dissociation between your reactions or a more “corrosive” substance, use HNO3 instead of HSO4.
Why can we not use concentrated hydrochloric acid and concentrated nitric acid for the preparation of hydrogen?
This is because nitric acid is a strong oxidising agent, and oxidises hydrogen gas to convert it into the water. While dil. sulphuric acid and dilute hydrochloric acid do not oxidise hydrogen into water hence preferred for the preparation of hydrogen gas.
Which acid is the weakest?
Strong acids are 100% ionized in solution. Weak acids are only slightly ionized. Phosphoric acid is stronger than acetic acid and so is ionized to a greater extent. Acetic acid is stronger than carbonic acid, and so on.
Strong and Weak Acids and Acid Ionization Constant.
| Acid | Conjugate Base |
|---|---|
| HCN (hydrocyanic acid) (weakest) | CN− (cyanide ion) (strongest) |
What’s the strongest acid in the world?
fluoroantimonic acid
The world’s strongest superacid is fluoroantimonic acid, HSbF6. It is formed by mixing hydrogen fluoride (HF) and antimony pentafluoride (SbF5). Various mixtures produce the superacid, but mixing equal ratios of the two acids produces the strongest superacid known to man.
Is hydrochloric acid a strong acid?
HCl is a strong acid because it dissociates almost completely. By contrast, a weak acid like acetic acid (CH3COOH) does not dissociate well in water – many H+ ions remain bound-up within the molecule. In summary: the stronger the acid the more free H+ ions are released into solution.
When testing a halide What is the purpose of adding dilute nitric acid solution before adding silver nitrate solution?
Carrying out the test
The solution is acidified by adding dilute nitric acid. (Remember: silver nitrate + dilute nitric acid.) The nitric acid reacts with, and removes, other ions that might also give a confusing precipitate with silver nitrate.
Why is nitric acid added to the halide ion test?
The nitric acid is added first to remove any carbonate ions that might be present – they would produce a white precipitate of silver carbonate, giving a false positive result for chloride ions.
Why we use HCl in sulphate test?
Answer: Hydrochloric acid helps to make solution acidic and the barium sulphate precipitate formed is insoluble which gives turbidity.
How do you differentiate between HNO3 and HCl?
HCl reacts with silver nitrate to give a white ppt. of silver chloride. On the other hand there is no reactionobserved when dil. Nitric acid is treated with silver nitrate solution.
Why is nitric acid used in qualitative analysis?
In all cases, dilute nitric acid is added to remove any interfering ions that can form precipitate with the added reagent. For example, any carbonate ions present would react with aqueous silver/barium/lead(II) nitrate to form white precipitate of silver/barium/lead(II) carbonate.
Why do we need to acidify solutions?
as when a solution containing small amounts of lead is heated, the residue is not completely soluble in water, owing to the formation of a little basic salt of lead, and the addition of some mineral acid is necessary to ensure a clear solution.
Is dilute sulfuric acid stronger than dilute nitric acid?
Perchloric acid is stronger than sulphuric and nitric acids and it is a potent oxidiser.
Concentrated and dilute acids.
| Acid | Density | Molarity (M) |
|---|---|---|
| Hydrochloric acid 36% | 1.18 | 11.65 |
| Nitric acid 70% | 1.42 | 15.8 |
| Perchloric acid 70% | 1.67 | 11.6 |
| Sulfuric acid 98% | 1.84 | 18.4 |
Which is worse nitric acid or sulfuric acid?
Between nitric acid and sulfuric acid, sulfuric acid is the more dangerous acid to work with by a modest margin because it is highly toxic in addition to being extremely corrosive.
What is the difference between sulfuric acid and nitric acid?
Sulfuric acid has 2 acidic hydrogens while Nitric acid has only 1 acidic hydrogen. This gives us the result that sulfuric acid will be more acidic than nitric acid in any solution, giving more number of H+ ions. Sulfuric acid is a stronger acid than nitric acid, which in turn stronger than acetic acid.
Why dilute nitric acid Cannot be used in preparation of hydrogen?
This is because nitric acid is a strong oxidising agent, and oxidises hydrogen gas to convert it into the water.
Why is dilute HCl stronger than highly concentrated acetic acid?
HCl is a strong acid, CH3COOH is a weak acid. Strong and weak acid refer to the degrees of dissociation. HCl acid ionises completely to H+ and Cl– ions (that is, about 100 out of 100 molecules donate their hydrogen ion).Hence, dilute HCl acid is stronger than highly concentrated acetic acid.
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