chem mcq...

[xHazeMx]

i know but m asking how wil know the structure is mixed in mcq paper how wil we decide itx 1 or 2 ???

give this a try

 

[sweetiepie]

2

 

[xHazeMx]

2

nope its 1

one C is bonded to 3 H atoms so its neglected, one C has double bond to O atom so it doesnt have 4 different atoms and the middle one is bonded to CH3 group , H which is hidden, COOH group and the OH group . these are four different groups pf atoms so the chiral centres are 1 only
did u understand the hidden H atom part ?

 

[sweetiepie]

no i dint m stil confused...

 

[xHazeMx]

usually when we write the skeletal formula or the ring formula of a compound we dont express the H atoms in between. obviously, carbon has 4 bonds, so if u look to the image again u will see that the middle C atom has 3 bonds to different groups, now we need 1 more different atom to have a chiral centre. whenever u see a C atom in the middle of a structure bonded to three groups of atoms, then the fourth one is H ( as i just mentioned above) now u have 4 different groups of atoms ( CH3, OH, COOH and H ).

the carbon atom on the right has two of its bonds bonded to O atom which means its not bonded to 4 different groups. As well as the carbon atom on the left side, its bonded to 3 H similar groups so we dont count that too. i hope everything is clear now

 

[sparten]

hmmm how to find chiral centre in a question like how wil know itx 2 or 3 or 4 m jux confused in that???

search for the carbon atoms which is bonded to four DIFFERENT atoms or group of atoms. each one is considered as one chiral carbon

all the bonds must b single covalent bond

 

[sweetiepie]

hmm thanks alot @xHazeMx .........

 

[xHazeMx]

hmm thanks alot @xHazeMx .........

you welcome

 

[sparten]

well its 1 coz one c has 3h bonds so neglect it,the middle c has on OH ,one methyl(cH3)group, one H and one cooH group...
as all groups are different and have sigma bonds so its chiral...
no other carbon in this compound setisfies this condition

 

[sweetiepie]

ooh stop stop it please i understood now dnt make me again confuse...

 

[xHazeMx]

ooh stop stop it please i understood now dnt make me again confuse...

lol sparten is just saying the same dont be confused. i think my explanation is more simple so just focus on that, it is just the same

 

[sweetiepie]

ya itx simplee..

 

[Ash1994]

hey how d0 you print these questions?
I tried taking a screen shot but it just won't work. . the whole page gets printed instead!

 

[fries25]

2 and 3 are correct (therefore, C). Two Cl atoms can not be added because Bromine is more polarisable while NaCl requires large amount of energy to be dissociated. Also, elements below in the electrochemical series get discharged preferrably.

As for the above question for the rate of reaction, the answer is C because the rate shall increase as products are formed that will catalyse the reaction. But also, there comes a point when the reaction gets completed and no more catalysis occurs hence the rate decreases afterwards.

 

[fries25]

2 and 3 are correct (therefore, C). Two Cl atoms can not be added because Bromine is more polarisable while NaCl requires large amount of energy to be dissociated. Also, elements below in the electrochemical series get discharged preferrably.

 

[xHazeMx]

hey how d0 you print these questions?
I tried taking a screen shot but it just won't work. . the whole page gets printed instead!

screen shot > photoshop program if u have it > crop the needed part > save as picture file > then just attach the saved file in ur post here

 

[alisha]

doubts: MAY/JUNE Q2 and Q10 (more to come thse first)

 

[alisha]

also: same paper Q11,15,33,38

 

[hassam]

 

[girlscampisra]

which year Alisha?