question on amphiteric substances (1 Viewer)

[namburger]

Lead (IV) Oxide can be classified as an amphiteric substance. Write 2 equations that represent this.

Is this question out of syllabus? Otherwise, how you do it =s

 

[minijumbuk]

Amphoteric oxides are not in the syllabus.

AmphIPROTic substances are.

 

[rooeys2]

lol nam did you do it?
amphoteric > amphiprotic so anything amphiprotic are classified under amphoteric.

you react lead oxide with water and hydrochloric acid to show its acidic and basic nature, i rkn it was a pretty dodgy question

 

[namburger]

lol nam did you do it?
amphoteric > amphiprotic so anything amphiprotic are classified under amphoteric.

you react lead oxide with water and hydrochloric acid to show its acidic and basic nature, i rkn it was a pretty dodgy question

Nah, i made up some random equation.
Could you write your equations, i checked wiki and it gave me this:

• with acid: PbO + 2HCl → PbCl₂ + H₂O
• with base: PbO + Ca(OH)₂ +H₂O → Ca²⁺[Pb(OH)₄]^2-

Still reckon its out of syllabus.

 

[Azreil]

Lead (IV) oxide is PbO2, just so you know.

Closest I could come up with was:

PbO2 (s) + H2O (l) + 2 e- --> PbO (s) + 2 OH- (aq)

Not sure about with HCl.

 

[Just.Snaz]

Lead dioxide is amphoteric. Lead dioxide can dissolve in strong base to form plumbate ion, Pb(OH)6 2−. This can then form plumbate compounds. In acid conditions, it is typically reduced to lead(II) ion, Pb2+; lead(IV) ion, Pb4+, is not found in aqueous solution.

http://en.wikipedia.org/wiki/Lead_dioxide

Amphoteric means it can react with an acid or a base. Amphiprotic means it can react as an acid or base.

The syllabus doesn't mention anything about amphoteric substances but still, knowing a little bit about it could make solving other questions easier. Although, if you get mixed up between the two then don't worry about it at all.

 

[minijumbuk]

Lead (IV) oxide is PbO2, just so you know.

Closest I could come up with was:

PbO2 (s) + H2O (l) + 2 e- --> PbO (s) + 2 OH- (aq)

Not sure about with HCl.

But firstly, H2O is neither an acid nor a base. I know that under some conditions it can be regarded as a Bronsted-Lowry acid or base, but I don't think that applies here. How can you have 2 substances that are amphiprotic to react? I don't know any extra-curricular stuff, but I just reckon that equation looks wrong. Especially the electrons. I don't recall any acid/base reactions having to deal with electrons.

Or maybe it's my limited scope of knowledge xD
So can someone please enlighten me? xD

 

[Azreil]

Honestly, I'm not sure how it works. That was just as good as I could come up with fiddling around xD That wasn't from the syllabus at all, it was from the introductory chemistry university course I did last year.

All in all, I think everyone agrees: The question sucked xP

 

[rooeys2]

Nah, i made up some random equation.
Could you write your equations, i checked wiki and it gave me this:

• with acid: PbO + 2HCl → PbCl<SUB>2</SUB> + H<SUB>2</SUB>O
• with base: PbO + Ca(OH)<SUB>2</SUB> +H<SUB>2</SUB>O → Ca<SUP>2+</SUP>[Pb(OH)<SUB>4</SUB>]<SUP>2-</SUP>

Still reckon its out of syllabus.

shit did the question say lead (IV) oxide? cuz i wrote PbO, im pretty sure it was lead (II) oxide =S dont scare me!
i might be wrong but this is what i wrote:
PbO + 2HCl → PbCl<SUB>2</SUB> + H<SUB>2</SUB>O
PbO + H2O → Pb(OH)2
i scribbled so many possible equations during the exam far out, only those 2 seemed right lol

 

[namburger]

The question was out of syllabus, so the examiners had to change their marking criteria lol. as long as you showed it reacted with an acid or base and disregarding the products, you will get full marks.

dodgy fort street science faculty =P