Chemistry: Post your doubts here!

[Ebrahim12]

Which fertilisers, when washed out of soil by rain, cause excessive growth of river plants and
algae with the result that fish in the river die?
1 K2SO 4
2 NH4NO 3
3 NaNO3

Only 2 and 3 are correct. Won't the K+ ions in 1 also cause excessive growth in plants?

 

[A*****]

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

Was going to ask the same!!

 

[A*****]

Is the boiling point of a compound directly proportional to percentage of carbon in the compound?

Never heard of that

how to find sigma and pi bonds and what are they?

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

 

[A*****]

Which fertilisers, when washed out of soil by rain, cause excessive growth of river plants and
algae with the result that fish in the river die?
1 K2SO 4
2 NH4NO 3
3 NaNO3

Only 2 and 3 are correct. Won't the K+ ions in 1 also cause excessive growth in plants?

Is it used as a fertilizer?

 

[Hamnah Zahoor]

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

Was going to ask the same!!

Well I suppose when we studied about molecules possessing energy we know that it is not the case that a very large number of molecules possess very low energy or very high energy I mean the peak of the graph never shifts to the far left or right in case of showing energy. Most molecule posses average energy thus option D is incorrect.
In option B at high temperature peak lowered showing the correct graph.

 

[Hamnah Zahoor]

Is it used as a fertilizer?

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.

 

[A*****]

Well I suppose when we studied about molecules possessing energy we know that it is not the case that a very large number of molecules possess very low energy or very high energy I mean the peak of the graph never shifts to the far left or right in case of showing energy. Most molecule posses average energy thus option D is incorrect.
In option B at high temperature peak lowered showing the correct graph.

but the peak is at almost the same energy level...I mean it is not shifted to the right

 

[SohaibButt]

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

 

[Hisham Khan]

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

It has to be D check again

 

[SohaibButt]

It has to be D check again

I checked it's B

 

[Hisham Khan]

I checked it's B

My teacher said it's D lol

 

[SohaibButt]

My teacher said it's D lol

She is not marking scheme

 

[Hisham Khan]

She is not marking scheme

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

 

[SohaibButt]

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

Yup man explain now! He must have given reason

 

[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