Deduce Bronsted-Lowry Base

Let's take a look at our discussion question this week!

221212 question

We want to determine if the underlined species are acting as Bronsted-Lowry bases.

Let us first understand what is an acid and base according to the Bronsted-Lowry theory.

221212 bronsted acid base

Bronsted acid is a proton (H+) donor.

Bronsted base is a proton (H+) acceptor.

The biggest difference between Bronsted-Lowry theory and Arrhenius theory is in the base.

Arrhenius base must dissolve in water to give OH-, while Bronsted base just need to accept H+.

Check out this video lesson for a detailed comparison of the 3 different acid-base theories.

Let's look at the 3 options and determine the Bronsted acid and base.

221212 option 1

NH4+ donates proton to form NH3, hence NH4+ is the Bronsted acid.

Underlined species H2O accepts proton to form H3O+, hence H2O is the Bronsted base.

Hence option 1 is correct.

221212 option 2

H2SO4 donates proton to form HSO4-, hence H2SO4 is the Bronsted acid.

Underlined species HNO3 accepts proton to form H2NO3+, hence HNO3 is the Bronsted base.

Hence option 2 is correct.

221212 option 3

It will be easier to deduce the acid and base if we separate NaNH2 into Na+ and NH2-.

CH3COCH3 donates proton to form CH3COCH2-, hence CH3COCH3 is the Bronsted acid.

Underlined species NH2- accepts proton to form NH3, hence NH2- is the Bronsted base.

Hence option 3 is correct.

Therefore all options are correct and the answer to this question is option D.

221212 answer

Topic: Ionic Equilibria, Physical Chemistry, A Level Chemistry, Singapore

Back to other previous Physical Chemistry Video Lessons.

Found this A Level Chemistry video useful?

Please LIKE this video and SHARE it with your friends!

Join my 10,000+ subscribers on my YouTube Channel for new A Level Chemistry video lessons every week.

Check out other A Level Chemistry Video Lessons here!

Need an experienced tutor to make Chemistry simpler for you?

Do consider signing up for my JC Chemistry Tuition classes at Bishan, weekly LIVE webinars or on-demand video lessons!