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Mr Yeong, why can't this be carbon?

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can explain why partial pressure directly propotional

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Mr Yeong, why is it not also correct to say ‘a slightly positive carbon atom’? When the carbon is surrounded by ED alkyl groups

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Mr Yeong, could you go through this question?

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For qn 19 why is x = 5 not possible. Is the drawing in red not possible?

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Mr Yeong, can I ask why option A is not correct?

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how to get the answer

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why is option 3 correct

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If a half cell does not contain a metal as the electrode(the electrode is not taking part in the reaction). If I use any electrodes other than platinum is it considered non-standard conditions

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Mr yeong why A wrong

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If a question asks how many possible products can form as a result of the elimination reaction do I account for isomers like cis-trans

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If transition is the highest for an elementary step, does this mean that this step is the rate-determining step

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Mr yeong, how is the answer C and not A?

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Mr yeong, can you go through this question?

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Could you go through this question?

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Mr Yeong, isnt option B also correct?

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This question too. I was stuck in calculating for the number of moles of electrons for Q = neF

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Mr Yeong, could you go through this question?

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Why is it W and Y and not W and X?

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For option A, shouldn’t the rate equation be rate = k[NO]^2[H2]^2? Because there is another H2 in the fast rxn

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also, for the compound on the left, does it undergo side-chain oxidation with acidified KMnO4..?

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can explain how to do

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Can u draw where the plane of symmetry is located how do you know the plane of symmetry they are asking for is not about the entire molecule

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Can u draw where the plane of symmetry is located how do you know the plane of symmetry they are asking for is not about the entire molecule

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Can you help me give a more detailed explanation?

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Mr yeong, for Q8, why is the 6th IE of As higher than S? Isn’t the electron to be removed in As 3d which is more shielded tha the 3s in S? How do we know that the effect from nuclear charge is larger and how are we supposed to know during examination?

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does this complex contain a ligand that is an alpha-amino acid

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how do you go about doing this qn?

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May I know why positive transition state is rejected

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Statement 1 is correct as the plane of symmetry is at the plane of the benzene ring.

Statement 2 is incorrect as there is only 1 planar intermediate formed. Can you explain this statement in greater detail

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Can you explain options 1 and 3

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Why is this considered a chiral carbon

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May I know how to do these type of questions?

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Mr Yeong, could you tell me how to approach Q21

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what’s the difference between B and D

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how to get G

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why is carboxylic acid stronger than phenol?

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for transition metals, can the center be central atom?

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for this q can I say: replace OH with Cl, replace Cl with CN, hydrolysed CN to COOH, use HVZ to ad the Br to form CH3CHBrCOOH, then eliminate to formCH2CHCOOH, then electronic add to ad water to form CH2OHCH2COOH, then oxidise?

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When do we use sum of enthalpy changes for reactants minus product and when do we use the sum of enthalpy changes for products minus reactants.

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why there ionic bonds between the ion in ii) if it only has a positive charge?

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How to know what electrode equations to use at what cases

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Why can NO3- undergo reduction instead of Ag+

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for rreaction kinetics when do we need to use 1/time taken as the rate

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how to form eqn for thermal decomposition

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Must we always specify the acid base reaction?

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Where is the carbon of the terminal alkene

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why is there a positive charge on O?

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we dont need to change cm cube to dm cube? why?

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mr yeong, why do we need to deduct by the last one for WS 20.12?

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Mr Yeong, I saw from the answer keys for acid base at MBC that the mol of weak acid and mol of salt is added up and then divided by two. Can I ask what is the rationale for this?

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where is the chiral carbon in Y

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If the question just say write an equation? do we have to include state symbols? will this be true even for questions from periodicity and transition metals

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can this be a possible structure for S

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For part (I), the question asked for the structure of protonated aspartic acid. Then shouldn’t the alpha Cooh be protonated instead of COO-?

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Mr yeong, could you help me with the working for concentration of CH3COOH and CH3COO-?

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How do we ensure that the buffer pKa +/- 1 coincides with a pH?

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For electrophilic addition of alkene, from alkene to alcohol, the condition & reagents are conc. H2SO4, cold, followed by H2O warm. Could you explain what is the use of conc. H2SO4 and why warm and not heat?

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When temperature increases, the Kw value also increases as the concentration of [H+] and [OH-] increases to a same extent. But why does pH < 7? Should not it remain at 7? Since OH- increases too

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what does it mean when in a buffer, the [weak acid] and [conjugate base] are at their highest concentration?

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What are the key things to know for electrochemical cell

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When we are drawing the set up, how do we know in which direction do electrons flow - which is anode and which is cathode? Is it we neeed to compare the E value?

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When we are drawing the set up, how do we know in which direction do electrons flow - which is anode and which is cathode? Is it we neeed to compare the E value?

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at ph12 how does the cooh become coo-? and how does oh change?

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at ph12 how does the cooh become coo-? and how does oh change?

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In what way are we able to use the expression [salt]/[acid] to describe things? How can we use them? Or what does it imply?

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In what way are we able to use the expression [salt]/[acid] to describe things? How can we use them? Or what does it imply?

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hi mr yeong, for free radical substitution must we show the arrows? its not in the notes but i saw it in a prelim answer key

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When to account for S2O8^2-/SO4^2- and nitrates etc during electrolysis

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what are the key formulas and info I need to remember regarding the titration curve

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Hello Mr yeong could you help me to consolidate these concepts: from N compound checklist. I still don't quite understand these

Explain what isoelectric point is a nd able to locate where is it on the titration curve?

Able to sketch the titration curve when NaOH is added to an amino acid

With the aid of equations to show how buffer for an amino acid (e.g. glutamic acid above) works at buffer region at pH = 4.1

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is it correct to say the p orbital of the O atom containing the lone pair of electrons overlaps with the pi electron cloud of the co double bond hence lone pair is delocalised into the into pi electron cloud of the carbonyl group?

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do we need to know how to name transition metal complexes?

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Is this answer acceptable ?

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Mr Yeong does this only apply for d and p orbital, because for Ca vs K, you can say that for K the half filled s orbital is extremely stable also

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can i draw the protonated form instead of the deprotonated form

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can go through the thought process for rate of reactions like hydrolysis where resonance takes priority over inductive effects

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Hi Mr Yeong can you please recap the hierarchy for factors determining acidity 

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Hi Mr Yeong can you please recap the hierarchy for factors determining acidity 

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Hi Mr Yeong, i the exam can we use the abbreviations like R - Oh and HX to denote a alkyl group attached to the hydroxyl group and hydrogen attached to hallide ion respectively?

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Mr Yeong, could you explain why the first electron affinity of oxygen is negative but subsequent electron affinity is positive?

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would my answer for aii work?

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since its an acid base reaction isnt it supposed to be a single arrow and not reversible?

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Mr Yeong, when we are calculating the number of the enantiomers using 2^n, are we counting the structure with at is given in the question? When do we 2^n -1 and when do we just use 2^n?

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why must we add hno3 when we test for chloroalkane

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Why does the reasoning for Insolubility in water not include “ insufficient to compensate for the energy taken in to overcome the hydrogen bonds between water molecules AND THE PD-PD ATTRACTIONS BETWEEN HALOGENOALKANE MOLECULES “ ? Cause i thought need to write solute-solute and solvent-solvent interactions

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Can i use heat instead of heat under reflux for all reactions

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more in comments

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what are lattice structures and which of them do we need to know

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mr yeong why is ii) reversible? doesn't NaCN dissolve to give ions and isn't NaOH a strong base

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What is the difference between aliphatic amide and aromatic amide?

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Mr Yeong, How did they get 122 (qn in the comments)

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Can I also ask how is A preferentially formed compared to C? What is the cause that Br is preferentially on 2- position rather than 4- position?

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Mr Yeong, could you explain how we can know which group is stronger activating group? Is it by the availability of lone pair?

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Mr Yeong, why is first IE of calcium higher than potassium, yes calcium has higher nuclear charge than potassium, but the electron removed from calcium is a paired electron and the one removed from potassium is not. Just like phosphorus vs sulfur, sulfur has higher nuclear charge but has lower IE because the electron removed from sulfur is a paired electron which experiences inter electronic repulsion, but why this does not apply for calcium vs potassium?

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i don’t understand the difference between this can u explain like technically isn’t both coo and cocl both highly electronegative atoms so why is it that carbon in carboxylic acid less electron deficient than acid chloride

then, comparing amides and acrylic chlorides, why is N able to delocalise its lone pair of electrons into the pi bond of c=o but Cl in cocl can’t?

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Mr Yeong, when I explain about the buffer system in blood, can I use H+ instead of H3O+?

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mr Yeong is my ans for the first one accepted? they said particles and didnt specify atoms or ions

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elaborate more in comments

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Could you please show me the derivation to this?