LockB's answer to LockB's Secondary 4 A Maths Singapore question.

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LockB
Lockb's answer
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^ the question
LockB
LockB
3 years ago
part a is about identify the correct substance from a list of given substance hence it is not related
J
J
3 years ago
I see...

False then.

The colour change is from purple to colourless.

Potassium manganate (VII) can only be reduced, not oxidised further.

The oxidation state of Mn in the MnO4- is +7.

This is reduced to +2 (Mn²+ ions are formed)


SO2 is a reducing agent here.


This question part is to test whether you remember the colour change correctly or not.

Quite a basic question.
J
J
3 years ago
Anyway, the maximum oxidation state of Mn is +7.

You can think of it as Mn7+ ion, though usually these don't exist as standalone ions.

It typically exists in the form MnO4-
LockB
LockB
3 years ago
thx :) btw for the qn :
"iron from thr blast furnace contains carbon and silivon as impurities. what is the source of silicon impurities in the blast furnace?"

why must it be sand and not slag? since slag also contain silicon
J
J
3 years ago
Slag is a byproduct, not a source.

The origin of the silicon (Si) comes from the silicon dioxide SiO2 which makes up the majority of most forms of sand.