Chemistry: Post your doubts here!

[MShaheerUddin]

View attachment 63810


Plz someone guide me on how to balance such equations...will be really grateful

Is this As level or A level?

 

[A*****]

Is this As level or A level?

As

 

[MShaheerUddin]

When BaCO3 and MgCO3 are heated they would produce their oxides, right?
and If they react with HCL then they wouldn't produce CO2 .. I think 1 is wrong but it isn't .. why?

 

[A*****]

View attachment 63850
When BaCO3 and MgCO3 are heated they would produce their oxides, right?
and If they react with HCL then they wouldn't produce CO2 .. I think 1 is wrong but it isn't .. why?

Barium carbonate does not decompose on heating using a busen burner

 

[MShaheerUddin]

Barium carbonate does not decompose on heating using a busen burner

._.

 

[MShaheerUddin]

View attachment 63810


Plz someone guide me on how to balance such equations...will be really grateful

Ans is C ?
if yes then I will post solution

 

[A*****]

Ans is C ?
if yes then I will post solution

It's B

 

[MShaheerUddin]

Yea i've got the answer but it is a bit difficult to explain .. give me a minute

 

[MShaheerUddin]

oxidation number of I in HIO is +1, in I2 is 0 and in HIO3 is +5
so HIO to I2 is (+1 -----> 0)x2 which is -2 because there is 2 Is in I2.
and HIO to HIO3 is (+1------>+5) which is +4
ratio is -2:4 is 1:2 so mol ratio must be 2:1

 

[A*****]

Yea i've got the answer but it is a bit difficult to explain .. give me a minute

Will be really thankful to u

 

[MShaheerUddin]

oxidation number of I in HIO is +1, in I2 is 0 and in HIO3 is +5
so HIO to I2 is (+1 -----> 0)x2 which is -2 because there is 2 Is in I2.
and HIO to HIO3 is (+1------>+5) which is +4
ratio is -2:4 is 1:2 so mol ratio must be 2:1

Don't you get it ?

 

[A*****]

oxidation number of I in HIO is +1, in I2 is 0 and in HIO3 is +5
so HIO to I2 is (+1 -----> 0)x2 which is -2 because there is 2 Is in I2.
and HIO to HIO3 is (+1------>+5) which is +4
ratio is -2:4 is 1:2 so mol ratio must be 2:1

Sorry I don't get it
Will u plz show that on paper if u don't mind?

 

[MShaheerUddin]

Understand?
If no, then let me know i will recommend you something

 

[MShaheerUddin]

Do you have a book of Lawrie Ryan and Roger Norris (the blue one) ?

 

[Kanekii]

How to know atoms lie in the same plane/straight line?
need help

 

[Hamnah Zahoor]

How to know atoms lie in the same plane/straight line?
need help View attachment 63860 View attachment 63853 View attachment 63854 View attachment 63855

Q: 1 Empirical formula is the simplest whole ratio which is only shown by option A C2H4O can not be further simplified.
Q: 3 I don't get it much either but to be a straight line compound should have a angle of 90 degree in it's compound to be straight.which is option D octahedral = 90
Q: 25 H2SO4 used to dehydrate i.e remove the alcohol group first by adding it than hydrogenate to remove the carbon carbon double bond. option A
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°.

 

[Kanekii]

Q: 1 Empirical formula is the simplest whole ratio which is only shown by option A C2H4O can not be further simplified.
Q: 3 I don't get it much either but to be a straight line compound should have a angle of 90 degree in it's compound to be straight.which is option D octahedral = 90
Q: 25 H2SO4 used to dehydrate i.e remove the alcohol group first by adding it than hydrogenate to remove the carbon carbon double bond. option A
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°.

Oh i understand now thank you so much
And one more thing can sulfuric acid dehydrate carboxylic acid?

 

[A*****]

View attachment 63859
Understand?
If no, then let me know i will recommend you something

Yeah I understand what u r saying but what will be the final equation? It is not balancing using these figures

 

[A*****]

Do you have a book of Lawrie Ryan and Roger Norris (the blue one) ?

Yesss

 

[Tajrina Promela]

I need help with these.

Can anyone explain why 30 isn’t C. According to what I’ve learnt about sigma bonds, 30 should be C.