Chemistry MCQ thread...

[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 :%) :Search:

Anyone???????

 

[hassam]

ya RYT

 

[hassam]

 

[xHazeMx]

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 :%) :Search:

Anyone???????

it's D just find the number of moles of each using n = m/Mr and find the molar ratio between both compounds

 

[xHazeMx]

C right ?

 

[diwash]

what was the answer of the R rated Q hassam ?...is it C

 

[Mobeen]

C right ?

why cant it be D ? :%)

 

[xHazeMx]

C right ?

why cant it be D ? :%)

let hassam confirm it first

 

[diwash]

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 :%) :Search:

Anyone???????

it's D just find the number of moles of each using n = m/Mr and find the molar ratio between both compounds

I think its A...
to find the % yield for each step...use the formula...yield = (given mass of product..44.64 for 1)/( mr of butanone) *100%...in this case...

 

[diwash]

i would Say...D.. hassam..

 

[xHazeMx]

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 :%) :Search:

Anyone???????

it's D just find the number of moles of each using n = m/Mr and find the molar ratio between both compounds

I think its A...
to find the % yield for each step...use the formula...yield = (given mass of product..44.64 for 1)/( mr of butanone) *100%...in this case...

i think u have to find it with moles formulas as it is known that 1 mole of butan-2-ol gives one mole of butanone.

 

[diwash]

ya ..we need to but in this case...the reactant side has Molar mass( no of moles is 1)...so i just wrote it directly..

 

[hassam]

If the equilibrium constant for the reverse reaction is
9.0 × 10−4, what is the equilibrium constant for the
forward reaction?
(A) 3.0 × 10−2
(B) −3.0 × 10−2
(C) −9.0 × 10−2
(D) 1 / 9.0 × 10−4
(E) 1 / −9.0 × 10−2

 

[xHazeMx]

If the equilibrium constant for the reverse reaction is
9.0 × 10−4, what is the equilibrium constant for the
forward reaction?
(A) 3.0 × 10−2
(B) −3.0 × 10−2
(C) −9.0 × 10−2
(D) 1 / 9.0 × 10−4
(E) 1 / −9.0 × 10−2

C for paravastatin question and D for the enthalpy question

 

[hassam]

EQUILIBRIUM ONE IS RYT BUT PARAVASTATIN one is D

 

[Ash1994]

http://www.xtremepapers.me/CIE/Internat ... _qp_13.pdf

Q 23 please

 

[Zishi]

EQUILIBRIUM ONE IS RYT BUT PARAVASTATIN one is D

Right. I got these answers. Potassium manganate(when heated under reflux) is so strong oxidising agent that it tends to break the chains.

 

[RafaySid]

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

It's damn easy Octahedral, I did this just this afternoon. Calculate the moles of reactant and the product formed. Such as 74.00 g of butan-2-ol or butan-1-ol will give you 1 mol. as 74 is the Mr. And so likewise 44.64 g of butanone or 54.56 g of butanoic acid will give you 0.62 moles, thus the percentage yield is 62%. Same is for the third part. The answer is A.

 

[xHazeMx]

EQUILIBRIUM ONE IS RYT BUT PARAVASTATIN one is D

oh thats correct i forgot about the additional bromine atoms

 

[xHazeMx]

EQUILIBRIUM ONE IS RYT BUT PARAVASTATIN one is D

Right. I got these answers. Potassium manganate(when heated under reflux) is so strong oxidising agent that it tends to break the chains.

which chains are most probably to be broken ?