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Any1 help me with mj 22 2011, q 1b)ii)
i dont understand why n(NaOH)=n(Hcl)
can any1 clarify for me pleasE? Thanks!
HCl + NaOH = NaCl + H2OAny1 help me with mj 22 2011, q 1b)ii)
i dont understand why n(NaOH)=n(Hcl)
can any1 clarify for me pleasE? Thanks!
u can make the four groups around the chiral carbon in any plane, it doesn't really matter and no marks will be deducted.I just wanted to know that when we are asked to draw a chiral compound,would the marks be deducted if I didnt draw it exactly as the way in marking scheme.Cuz almost all the times the position of 4 groups around chiral carbon in my structure are different from the structure given in marking scheme.And generally when writing structural formulae i cannot write them exactly as mentioned in marking scheme??
wats the bond angle and shape of a compnd with 2 bond pairs and 1 lonepair
http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w10_qp_23.pdf
4b(ii) --> how does the elimination reaction produce "ethane" doesn't elimination produce alkene? :/
That's a typo in the Mark Scheme. They meant to write Ethene; they've written the formula of Ethene, C2H4. Ethane is C2H6.
It forms a double bond with both..
http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s09_qp_2.pdf
Question 5 part (f)
How do we draw the structure of S?
3 bond pairs with 1 lone pair would be triangular pyramidal - 107. I havent come across 2 bond pairs with 1 lone pair as 2 bond pairs and 1 lone pair would give 6 electrons not a complete 8
o_o But how are we supposed to figure this out? I am still kind of confused.. even after looking at step I again and again..CH3CH(OH)CH2CH2CHO
the C=O bond on the first aldehyde is broken and an O-H bond is formed between the O in the first aldehyde and the hydrogen from the CH3 in the second aldehyde.
basically, it's an addition reaction.
o_o But how are we supposed to figure this out? I am still kind of confused.. even after looking at step I again and again..
Thanks, I get it now. Drawing the displayed formula of the aldehyde reaction to make T really did help. Still, I think this is a pretty tricky question.It might seem complicated but it's easier if you work backwards. the question says that T has an OH group. and U is formed from T.
U has a double bond, which was formed when T was dehydrated and the alcohol group was removed. As the = is between the second and the third carbon the -OH group also has to be on either the second or third carbon. but as T was formed from 2 aldehydes it be on the third because otherwise you would have 2 aldehyde groups in T. Therefore the formula of T was CH2CH(OH)CH2CHO.
you know that T was formed form two aldehyde molecules. CH3CHO and CH3CHO
when you see the formula of T you can easily guess that the C=O bond in one of the aldehyde has been broken and the two molecules re joined by O with the initial C-O bond still in place and a newly formed O-H bond with hydrogen atom of the CH3 part of the second aldehyde. The same happens while predicting the structure of S.
PS. It helps if you draw the displayed formula of the aldehydes and T if you're confused.
Thanks, I get it now. Drawing the displayed formula of the aldehyde reaction to make T really did help. Still, I think this is a pretty tricky question.
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