Hi, I've just noticed a few different things and got numerical answers to some of the different calculations below, let me know if you disagree.
9 should be A, 10 should be D, 12 should be A, 25 should be C.
1a) sqa probably would accept 5th/7th/9th electron. c) gives K = 3.2 x 10^-5
2a) Order of a reaction is the power to which a concentration is raised in the rate equation.
2c) In Hess' law style from Higher, gives: H2O2 + 2I- + 2H3O+ + I2 + 4H2O
3b)i) Distilled/deionised water is used to set a colorimeter
b)ii) Agreed with you that its 35.5% - think SQA would accept that 35.5% or 71% because the wording lacks a bit of clarity.
4aii) HO2- b) genuinely ahahah
c) ii) A - 0.08 mol l-1 B - pH = 1.95
5bii) This has nothing to do with d shells / special stability as when a transition metal is in a complex, the d-orbitals are no longer degenerate - question does specify that this question is about transitions. (This is according to my teacher) Hence I think they'd be looking for something like stating that d-orbitals are no longer degenerate and therefore when electrons transition from the lower orbitals to the higher orbitals, the energy absorbed does not correspond to a wavelength in the visible spectrum.
c) i) E = 2.04 x 10^-16 J ii) 18.96 eV
6a) I got 10.5 mol l-1. Question is very similar to one from 2016 or 2017 paper about bleach.
6c) could also talk about the indicator being faulty or there being a high uncertainty in the end point.
7b)i) When atomic orbitals overlap sideways. ii) When two p orbitals and an s orbital merge to form 3 hybrid orbitals.
7c) Probably looking for a statement like 'electrons delocalised in a conjugated system'.
7d)ii)(C) (I) 0.029m (II) 4.065 x 10-3 kJ mol-1
9a)ii) chiral molecules that are non-superimposable mirror images of eachother
10bii) 2-methoxy-2-methylpropane
10ciii) Provides a more stable carbocation due to the inductive stabilisation of the carbocation.
10d) Mirror image wouldn't be optically active. Butan-2-ol however is an isomer that is chiral and hence optically active.