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Chemistry: Post your doubts here!

MShaheerUddin

MShaheerUddin

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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
 
MShaheerUddin

MShaheerUddin

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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 ? :D
 
A*****

A*****

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MShaheerUddin said:
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
Click to expand...
Sorry I don't get it :(
Will u plz show that on paper if u don't mind?
 
Hamnah Zahoor

Hamnah Zahoor

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Kanekii said:
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
Click to expand...

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

Kanekii

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Hamnah Zahoor said:
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°.
Click to expand...
Oh i understand now thank you so much :D
And one more thing can sulfuric acid dehydrate carboxylic acid?
 
Hamnah Zahoor

Hamnah Zahoor

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Tajrina Promela said:
View attachment 63883 View attachment 63884 View attachment 63885 View attachment 63886 View attachment 63887 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.
Click to expand...

Q 11
First balance the equation using oxidation states
5Sn(2+) + 2Mn(7+) ---------> 5Sn(4+) + 2Mn(2+)
moles of Sn= 0.05
0.05*(2/5) = 0.02 mol
thus option B

Q 24
Option D first add potassium cyanide ( better than HCN )
it will substitute Chlorine with CN
as we need to add one more Carbon in the chain
then for hydrolysis NaOH will be added to form the given product.

Q 27
When alkaline aqueous iodine is treated with 3 methyl butane it will form the following product.
111.png
Na will not be included as it only states alkaline not mentioned specific.

Q 30
Double bond is more stronger than single thus in poly(ethene) bonds are weaker and more weaker the bond is more longer it is.
 
MShaheerUddin

MShaheerUddin

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A***** said:
Yeah I understand what u r saying but what will be the final equation? It is not balancing using these figures
Click to expand...
The simplest ratio of 4:2 is actually the value of n and p
These value are find using the above method
Then we would balance q
Finally we will balance the reactants (m)

This is the typical method followed when balancing the equation using Valancies
Turn to page 112 of the book and see worked examples
 
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