Chemistry: Post your doubts here!

[Hamnah Zahoor]

He was a examiner in the practicals but yes we all are humans

Then better explain it.

 

[A*****]

Come on Hisham prove urself here as well

 

[SohaibButt]

Y he always act like a coward when comes to explanation -smh-

 

[Hamnah Zahoor]

For the same plane angle must not be 120? Here it is B but propane forms 109.5View attachment 64009

Q37 For a molecule to be in same plane it should have an angle of 120 degree in its compound
option A contains a 120 degree angle due to C=C bond.
I think option B have planar structure for it can also exist as cyclopropane which have angle of 120 degree ( I don't get this part either)
From the examination report:
Question 37 The most commonly chosen incorrect answer was C. This suggests that most candidates knew that the three carbon atoms in propane all lie in the same plane. The six carbon atoms in 2,3-dimethylbut-2-ene also all lie in the same plane, since the bond angles at an sp2 hybridised carbon atom are very close to 120°, and the π bond prevents rotation. However, the six carbon atoms in cyclohexane do not lie in the same plane, they are all sp3 hybridised with bond angles close to 109°.

 

[khadijaimran]

Well yes it is used as a fertilizer
The dominant use of potassium sulfate is as a fertilizer. K2SO4
But I am also not able to figure out why it is not involved in eutrophication.
Well It is also soluble in water.

eutrophication is only caused by excess amount of nitrates and phosphates in water bodies.

 

[A*****]

I think option B have planar structure for it can also exist as cyclopropane which have angle of 120 degree ( I don't get this part either)

Cyclopropane is not planar

 

[Hamnah Zahoor]

eutrophication is only caused by excess amount of nitrates and phosphates in water bodies.

Oh... Ok Thank You

 

[SohaibButt]

Q37 For a molecule to be in same plane it should have an angle of 120 degree in its compound
option A contains a 120 degree angle due to C=C bond.
I think option B have planar structure for it can also exist as cyclopropane which have angle of 120 degree ( I don't get this part either)
From the examination report:
Question 37 The most commonly chosen incorrect answer was C. This suggests that most candidates knew that the three carbon atoms in propane all lie in the same plane. The six carbon atoms in 2,3-dimethylbut-2-ene also all lie in the same plane, since the bond angles at an sp2 hybridised carbon atom are very close to 120°, and the π bond prevents rotation. However, the six carbon atoms in cyclohexane do not lie in the same plane, they are all sp3 hybridised with bond angles close to 109°.

Yup it should not be propane then

 

[A*****]

This is the shape of propane so yes it is planar

 

[khadijaimran]

Someone pls help it's ans is B y not D?View attachment 64008

which year is this?

 

[Hamnah Zahoor]

Cyclopropane is not planar

Then how do you prove propane to be planar I even searched it on the internet but I was not able to get the idea and on some sites it stated cyclopropane to be planar.
I am still confused on this part.

 

[SohaibButt]

View attachment 64010

This is the shape of propane so yes it is planar

But it is not condition angle must be 120?

 

[Hamnah Zahoor]

View attachment 64010

This is the shape of propane so yes it is planar

Thank you so much.

 

[SohaibButt]

which year is this?

Nov/04

 

[A*****]

Then how do you prove propane to be planar I even searched it on the internet but I was not able to get the idea and on some sites it stated cyclopropane to be planar.
I am still confused on this part.

I've searched for it multiple times but the explanation about cyclopropane not being planar is beyond our syllabus and I don't get it...anyways our mark schemes always refer to it not being planar so just remember this

 

[A*****]

Then how do you prove propane to be planar I even searched it on the internet but I was not able to get the idea and on some sites it stated cyclopropane to be planar.
I am still confused on this part.

I've searched for it multiple times but the explanation about cyclopropane not being planar is beyond our syllabus and I don't get it...anyways our mark schemes always refer to it not being planar so just remember this

 

[SohaibButt]

I've searched for it multiple times but the explanation about cyclopropane not being planar is beyond our syllabus and I don't get it...anyways our mark schemes always refer to it not being planar so just remember this

But pls tell me it is not necessary angle must be 120?

 

[A*****]

But it is not condition angle must be 120?

No I don't think so

 

[Kanekii]

Never heard of that


Sigma bond is the single bond formed due to overlap of orbitals....pie is formed by the sideways overlap of p orbitals

So sigma bond can be any bond? Or im confused :/

 

[A*****]

So sigma bond can be any bond? Or im confused :/

It actually is a bit confusing....every first bond bw two atoms is sigma and the rest are pie