In Chemistry, the most important essential concepts is to understand the chemical definition of a term. This will allow you answer tricky exam-based questions with less stress, as you can draw upon your knowledge on “definition” which will not be incorrect.
An acid is a compound, which produces hydrogen ions (H+) as the only +ve ions when dissolved in water.
When HCl (a covalent molecule) is bubbled into water, it ?dissolves? to form H+ ions & Cl- ions known as Dissociation or Ionisation.
We say HCl dissociates into H+ ions & Cl- ions when dissolved in water
HCl(aq) –> H+(aq) + Cl-(aq)
Acids only have Acidic properties when they are dissolved in water.
If water is absent, an acid does NOT show its acidic properties.
All acids contain hydrogen atom but not all substances that contain hydrogen are acids.
E.g. Ammonia & Methane are not acids even they contain Hydrogen atoms in their chemical formulae
Let’s check out a question to see if you understand.
Quick Check 1:
Which of the following ions is not present in aqueous sulphuric acid?
A. H +
B. OH –
C. SO3 2-
D. SO4 2-
PS: Do leave your suggested answers in the “Comments Section” directly below this post.
PPS: This post belongs to a series of blogposts that is associated with Secrets of “Acids, Bases & Salts and Qualitative Analysis revelaed”
Theoretically there are only 4 as stated in most textbooks in basic chemistry syllabus.
1) Acid + Alkali -> Salt + Water (Neutralization)
2) Acid + Insoluble Base -> Salt + Water (Neutralization)
3) Acid + Metal (reactive) -> Salt + Hydrogen Gas
4) Acid + Carbonate -> Salt + Water + Carbon Dioxide
Hmm. If you insists on having the 5th one, i can only think of one reaction in the topic of ‘Precipitation of Insoluble Salt’.
5) Salt Solution A (aq) + Acid Solution B (aq) -> Insoluble Salt C (s) + Acid Solution D (aq)
e.g. AgNO3 (aq) + HCl (aq) -> AgCl (aq) + HNO3 (aq)
Hope the above information helps.
PS: If you happen to know of other reactions involving acids, do share with us here. Anyone is welcome to share your Chemistry knowledge in this blog.
Cheers!
Sean Chua
i need to know 5 chemical reactions of a acid; can you help me?
The think answer is C because H+ ions come from water, OH – ions also come from water and the SO4 2- ions come from sulphuric acid. SO3 2- ions is not contained in aqueous sulphuric acid
Hey Adithya,
Whenever aqueous, there will be water around and it will dissociates to give the hydrogen and hydroxide ions.
Hope this is clear.
Sean
Hey Chuahs,
May i know which educational level are you at right now?
And also which country you are from?
This would allow us to help you with the necessary answers and knowledge.
Sean
huh? it should be b. OH- is for alkali
what kind of gas will form when react HCL(1part)+H2O2(1part)+H2O(5parts)
Hey Jen,
Good to see you back here contributing again. Hope things gog fine on your side.
You are absolutely spot on! Answer shall be C, since the rest of the answers shows ions that can come from either water or Sulphuric Acid molecules.
Keep up the good work!
Rgds
Sean
Hey again.
I would go for answer c
because aq H2SO4 only contains
H+ ions (from water and sulphuric acid
OH- ions (from water)
SO4 2- ions (from sulphuric acid)