Chemistry MCQ thread...

[Zishi]

There are six double bonds.

no there is 5 C=C and 1 C=O check it again. C=O cant be hydrogenated. i guess the answer is A

LOL! No there are 6 double bonds. :lol:

Plus I really want to see your "doubtful" information on that polymer question....

well i guess h2 cn reduce.... c=0 saw it somewher in theory ms
here it is NaBH4 or LiAlH4 or H2/Ni (1) /....this is taken from m/j 08 p2 ms...zishi !!!

But answer still remains B.

 

[abdullah181994]

why is it 1 only???

benzene ring is large structure and non polar needs high energy to be soluble so not easily soluble.

 

[xHazeMx]

LOL! No there are 6 double bonds. :lol:

Plus I really want to see your "doubtful" information on that polymer question....

5 C=C and 1 C=O makes it 6 double bonds but can the C=O be hydrogenated?
and about that monomers question, is it because the polymer is made up from many monomers so the 1 mole of monomer will form (THEORETICALLY) number of moles in 2 and 3?,i mean 1 mole of monomers can form 1 mole of polymer right? :roll:

 

[Zishi]

LOL! No there are 6 double bonds. :lol:

Plus I really want to see your "doubtful" information on that polymer question....

5 C=C and 1 C=O makes it 6 double bonds but can the C=O be hydrogenated?
and about that monomers question, is it because the polymer is made up from many monomers so the 1 mole of monomer will form (THEORETICALLY) number of moles in 2 and 3?,i mean 1 mole of monomers can form 1 mole of polymer right? :roll:

Man, see the structure clearly, there are 6 C=C. lol

 

[xHazeMx]

LOL! No there are 6 double bonds. :lol:

Plus I really want to see your "doubtful" information on that polymer question....

5 C=C and 1 C=O makes it 6 double bonds but can the C=O be hydrogenated?
and about that monomers question, is it because the polymer is made up from many monomers so the 1 mole of monomer will form (THEORETICALLY) number of moles in 2 and 3?,i mean 1 mole of monomers can form 1 mole of polymer right? :roll:

Man, see the structure clearly, there are 6 C=C. lol

THIS IS CRAZY !! .. there are 6 double bonds but the last one in the bottom to the right is bonded to O ATOM isnt it? i m gonna lose my mind soon :%) :%) :crazy: :crazy:

 

[abdullah181994]

http://www.xtremepapers.me/CIE/International%20A%20And%20AS%20Level/9701%20-%20Chemistry/9701_s08_qp_1.pdf Q 23, 26, 27, 30 AND 39

PLEASE SOLVE THEM !!! THNX I DONT HAV SCREEN SHOT OPTION

please solve them !! ill be thnkful to u guys !!

23
26:C MOLECULAR FORMULAE SHOW THAT IT IS DI CARBOXYLIC ACID AND ONLY PRIMARY ALCHOLS COULD BE OXIDISED TO C.A.

 

[ninjas4life]

can anyone explain Q27 and for Q28 why cant the answer be c?

 

[xHazeMx]

http://www.xtremepapers.me/CIE/International%20A%20And%20AS%20Level/9701%20-%20Chemistry/9701_s08_qp_1.pdf Q 23, 26, 27, 30 AND 39

PLEASE SOLVE THEM !!! THNX I DONT HAV SCREEN SHOT OPTION

please solve them !! ill be thnkful to u guys !!

Q 23, its D because compounds having carbon atoms from 1 - 4 are gases which can be collected in the inverted tube because they r gases
Q 26, its C because 2 atoms of oxygen are added and 4 H atoms are removed indicating that after oxidation there are 2 carboxilic groups ( COOH ) and this would be the result from primary alcohols only so the OH should be on the first and fourth carbon
Q 27, its D because it is the result of dehydrating tertiary alcohol which is unreactive towards mild oxidising agents.
Q 30, its C because the X has been oxidised to an acid ( having 6 C atoms , hexanoic acid ) added to ethanol alcohol to produce an ester. the group behind the COO group is the acid formed by compound X
Q39, its B ( 1 and 2 ) because there are a secondary alcohol group which doesn't form aldehyde on oxidation but it reacts with sulphuric acid forming an ester, when bromine is added to cholesterol, it forms 2 new chiral carbons. u can figure them out easily
i hope this helps u

 

[xHazeMx]

can anyone explain Q27 and for Q28 why cant the answer be c?

Q 27 its C because irradiation emits only Cl* because C-Cl bond is weaker than C-f bond so the so the C atom which was bonded to the librated Cl will be written as C* which is the option C
Q 28 its C because each OH group in an acid or an alcohol ( ONLY ) gives off half mole of hydrogen so in C there are 2 OH groups which gives off 1 mole of hydrogen ( H2 )

 

[xHazeMx]

An experiment is set up to measure the rate of hydrolysis of methyl ethanoate.

CH3CO2CH3 + H2O CH3CO2H + CH3OH
The hydrolysis is found to be slow in neutral aqueous solution but it proceeds at a measurable
rate when the solution is acidified with hydrochloric acid.
What is the function of the hydrochloric acid?

A to dissolve the methyl ethanoate
B to ensure that the reaction reaches equilibrium
C to increase the reaction rate by catalytic action
D to suppress ionisation of the ethanoic acid formed

 

[xHazeMx]

How does ammonia behave when its aqueous solution is used to dissolve silver chloride, AgCl ?

A as a base
B as a ligand with the Ag+ ion
C as a ligand with the Cl– ion
D as a reducing agent

EXPLANATION ????

 

[Abdulrab]

D IS THE ANSWER ???

 

[xHazeMx]

D IS THE ANSWER ???

No

 

[histephenson007]

Could any1 plz explain this question? plzz...

 

[Abdulrab]

PLEASE ANSWER TO MY QUESTIONS ON PG 61 ! THANX

 

[histephenson007]

Another question...

this time I have another question..

When finding chiral centres in cycloalkanes...how do u differentiate if there is a chrical centre or not... In this case, how should I know that A doesn't have a chiral centre and D does??

 

[xHazeMx]

PLEASE ANSWER TO MY QUESTIONS ON PG 61 ! THANX

i answered them ! check the previous posts

 

[Abdulrab]

1 AND 2 !!! @ HISTHE....

 

[histephenson007]

1 AND 2 !!! @ HISTHE....

Which question r u talking about??

The one from section b?? then, its wrong

 

[Abdulrab]

I CANT FIND THEM WHERE R THEY ??? TELL ME THE PG NO !! @ Xhazemx