Page 1 of 1

6th ed: Fundamentals J.1

Posted: Sun Dec 02, 2018 2:22 pm
by Hannah Morales 1D
How do you determine whether a compound is a bronsted base or acid?
a) NH3 b) HBr c)KOH d) H2SO3, e) Ca(OH)2

Are there any tips when deciding whether something is an acid or base (Bronsted)?

Re: 6th ed: Fundamentals J.1

Posted: Sun Dec 02, 2018 4:04 pm
by Edward Xie 2E
A Bronsted acid is a proton donor, and a Bronsted base is a proton acceptor.

In this case, NH3 is a base, HBr is an acid, KOH is a base, H2SO3 is an acid, and Ca(OH)2 is a base.

One tip I generally use is I look at the chemical equation and see which substance loses a proton and which one gains a proton, which determines which is an acid or base.

Re: 6th ed: Fundamentals J.1

Posted: Sun Dec 02, 2018 4:14 pm
by Alma Carrera 3C
But how would you know which ones lose a proton and which ones gain a proton?

Re: 6th ed: Fundamentals J.1

Posted: Sun Dec 02, 2018 11:14 pm
by Edward Xie 2E
Alma Carrera 3C wrote:But how would you know which ones lose a proton and which ones gain a proton?


See which chemical gains/loses an H+.

For example: HCl(aq) + NH3(aq) → Cl(aq) + NH4+(aq)
HCl would be the acid because it donates a proton to NH3 and becomes Cl-.
NH3 would be the base because it accepts the proton from HCl and becomes NH4+.

Re: 6th ed: Fundamentals J.1

Posted: Sun Dec 02, 2018 11:17 pm
by Jeremy_Guiman2E
If something can produce/donate an H+ ion, it is probably a Bronsted acid. But, if it can accept one, it is a Bronsted base. The base is often OH-, but as you can seen, ammonia (NH3) can also act as a Bronsted base (proton acceptor) to produce ammonium ion, NH4+.