Chemistry MCQ thread...

[diwash]

thats an R rated questiom

I would go with C..

 

[xHazeMx]

i didnt understnd that question completely,,,i don understand where thos powers came from ans is B...CN anyone clear me this
well S has 6e- so 2 went in single bonds and 2 in double bond...so wheres the other 2

what is the answer for the angles question??

 

[hassam]

36 This question is about the chemistry of Group VII elements. Which of the following
statements are correct?
1 The halogens all form hydrides that are acids in aqueous solutions.
2 The reactivity of halogens as oxidising agents decreases on descending the group.
3 The reaction between concentrated sulfuric acid and potassium chloride is that of a
redox reaction.

 

[abdullah181994]

both Sn1 and Sn2 have intermediates
its just that the Sn2's intermediate is a very fast step such that it is often ignored.

aha, so if they ask which one has intermediate steps (like in a 1,2,3 question) , is it yes for SN2??

i dunno for sure because nothing like this came up before. but i'll put a yes for my own answer cause when you draw out the mechanism, you include the intermediate stage too rite?

in SN2 from reactants into>intermediate is a slow step from intermediate to product it is fast because
*intermediate has high energy and is unstable.
In SN1 no intermediate formed instead cabocation formed as a result C-X bond broken as bond breaking is endothermic so its a slow step and second is fast and exothermic as bond formed.

 

[ideggkr]

thats an R rated questiom

I think it's because after oxidation with H2SO4

there are 5 chiral centres left

and for each of new double bond formed, there are two possibility

2^5 multiplied by 2^2 ..?

 

[xHazeMx]

36 This question is about the chemistry of Group VII elements. Which of the following
statements are correct?
1 The halogens all form hydrides that are acids in aqueous solutions.
2 The reactivity of halogens as oxidising agents decreases on descending the group.
3 The reaction between concentrated sulfuric acid and potassium chloride is that of a
redox reaction.

D

 

[ideggkr]

@hassam

plz answer this.

It's about the question with red 'tough' written on it
---------------
Why is Y like that?

I thought Y was the product when the fluo-sth undergoes hydrogenation

Shouldn't the ketone group intact?

 

[hassam]

angle question ans is A.....

 

[diwash]

36 This question is about the chemistry of Group VII elements. Which of the following
statements are correct?
1 The halogens all form hydrides that are acids in aqueous solutions.
2 The reactivity of halogens as oxidising agents decreases on descending the group.
3 The reaction between concentrated sulfuric acid and potassium chloride is that of a
redox reaction.

Answer is B...

 

[hassam]

YES ITS B diwash

 

[abdullah181994]

thats an R rated questiom

i think its C 2^8 is it right

 

[Octahedral]

39 Use of the Data Booklet is relevant for this question.

In an organic synthesis, a 62 % yield of product is achieved.

Which of these conversions are consistent with this information?
1 74.00g of butan-2-ol → 44.64 g of butanone
2 74.00g of butan-1-ol → 54.56 g of butanoic acid
3 74.00g of 2-methylpropan-1-ol → 54.56 g of 2-methylpropanoic acid

 

[Xthegreat]

angle question ans is A.....

BINGO!

 

[xHazeMx]

angle question ans is A.....

how angle Y is 110 ? :Search:

 

[Xthegreat]

angle question ans is A.....

how angle Y is 110 ? :Search:

to be more accurate, angle Y is 107'

3 bonded pairs and 1 lone pair, doesn't that remind youj of NH3?

 

[rahultaneja2010]

Can sm1 teach me how to find bond angles plz ..? I always get it wrong

 

[hassam]

...well ketone group will not be intact cos a theory markscheme said that u cud reduce ketones or aldehydes using Hydrogen gas !!!

 

[xHazeMx]

angle question ans is A.....

how angle Y is 110 ? :Search:

to be more accurate, angle Y is 107'

3 bonded pairs and 1 lone pair, doesn't that remind youj of NH3?

right, though 110 indicates that there is no lone pair :unknown:

 

[hassam]

 

[xHazeMx]

it's A