Thanks for ur explanation !!!
I'm not fully understanding the problem yet
Is it :
I want to study the solubility of CaC2O4.
In this case, the solubility of CaC2O4 in high pH(alkaline
conditions)
In a way, we want to study the effect of [H+] in the solubility
of CaC2O4. (Can be seen from Wilber's equation)
In part iii) , the [H+] plays a role, in protonating anion, in
turn having an effect in the solubility of CaC2O4.
However in part iv) , we actually want to study the effect of
[H+] in high pH, but however, the NaOH actually causes increased
solubility of CaC2O4, as it precipitates out the cation, instead of
due to the effect of [H+] , which we want to study.
Is it?
For part iii) , the solution elucidates about the effect
of LCP for the explanation. But can i also explain , based on the
equation given in part iii, solubility increases, as total [H+] in
numerator increases faster than total [H+] in denominator, hence
solubility increases
Wrong, in high pH, it's OH- that's relevant, not H+. "We" do *not*
want to study the effect of [H+] in high pH, "We" only want to
study the effect of pH on solubility, so Wilbur's equation
(involving H+) is obsolete and can be retrenched.
Your mathematics-based answer will not be acceptable, because
firstly, the H2 Chem syllabus is always testing students about
shifting of position of equilibrium (use of acronyms like LCP not
allowed in A level exams); and secondly, the actual question (on
Wilbur's work, or similar) in the A levels might not give you an
mathematical equation or formula at all, so if all you can give are
mathematical reasonings (as opposed to chemical reasoning that's
required by the mark scheme), you'll be screwed in the A
levels.
BedokFunland JC exam tip : If you're exam-smart, you'll give a
variety of reasons, whatever you can think of. As long as they
don't contradict each other, you'll be given credit for whichever
answer Cambridge wanted.
