How to tell if it is an acid or base?

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Madeera_Mian_3B
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Joined: Fri Sep 28, 2018 12:24 am

How to tell if it is an acid or base?

Postby Madeera_Mian_3B » Thu Dec 06, 2018 7:13 pm

The 7th edition textbook problem Fundamental J 1, identify which is a Bronsted Acid or Base: NH3, HBR, KOH, H2SO3, Ca(OH)2. How do we know which one is a Bronsted acid or base?

Lumbini Chandrasekera 1B
Posts: 63
Joined: Fri Sep 28, 2018 12:18 am

Re: How to tell if it is an acid or base?

Postby Lumbini Chandrasekera 1B » Thu Dec 06, 2018 7:16 pm

You can tell from the chemical formula whether it is likely to produce H+ protons (acid) or OH- hydroxides (base), but for something like NH3 you would have to see what is would do when adding water. When adding water, it would form NH4+ and OH-, which is a hydroxide, making NH3 a base.

Esther Ahn 4I
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Joined: Fri Sep 28, 2018 12:29 am

Re: How to tell if it is an acid or base?

Postby Esther Ahn 4I » Thu Dec 06, 2018 7:18 pm

Acids also tend to have the form HA where A is an element and bases tend to have the form BOH where B is an element.

LuisG14A1J
Posts: 9
Joined: Fri Sep 28, 2018 12:17 am

Re: How to tell if it is an acid or base?

Postby LuisG14A1J » Thu Dec 06, 2018 7:25 pm

Acids and bases are generally visible whether something has H or OH ions within the compound. NH3 just has to be known that Ammonia is a weak base. There are some several compounds that just have to be known what they are so we can use them quickly and commonly.
To also find out if a compound is acidic or basic is if has electron lone pair, in this case NH3 has 1 open lone pair that means it is able to accept a hydrogen, though weakly (not too much), which makes it a weak base.

Typically, everything with the H in the front is denoted that way to give that indicator that the Hydrogen atoms can be stolen or traded in acid or base reactions.
In the examples given, It should be simple enough to see that those with the Hydrogen indicators in the front are acidic and those with the Hydroxide ions (OH) are basic. H2SO3 is a weak acid.
"any acid that is not one of the seven strong is a weak acid (e.g. H3PO4, HNO2, H2SO3, HClO, HClO2, HF, H2S, HC2H3O2 etc.)

Those are weak acid examples.

These are the main 7 strong acids for low level chemistry.
HCl, HBr, HI,
,HNO3, H2SO4, HClO4, & HClO3

John Kim Lec3Dis3L
Posts: 23
Joined: Fri Sep 28, 2018 12:17 am

Re: How to tell if it is an acid or base?

Postby John Kim Lec3Dis3L » Fri Dec 07, 2018 3:33 am

A general rule of thumb is to see whether the molecule predominantly contains (H^+) or (OH^-). Hope this helps!


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