Chemistry: Post your doubts here!

[gary221]

Only tertiary halogenoalkanes undergo SN1 Mechanism so the answer has to be C or D. We know iodide ions give yellow precipitate with AgNO3. So the answer is D>>

 

[mominzahid]

Assalam-o-alaikum wr wb..
Only halogenoalkanes undergo SN1 Mechanism so the answer is either C or D. We know iodide gives yellow precipitate with AgNO3. So the answer is D.

I dont get it but A and B are also Halogenoalkanes? why isnt it B ?

 

[gary221]

I dont get it but A and B are also Halogenoalkanes? why isnt it B ?

yea bt like i said only TERTIARY halogenoalkanes undergo SN1...

 

[mominzahid]

the answer is B because its 2nd degree alcohol which gives ketone when oxidised by potassium dichromate

Thankyouu.

 

[mominzahid]

yea bt like i said only TERTIARY halogenoalkanes undergo SN1...

Ahhh.. GOT IT.. Thanksss.

 

[mominzahid]

can u answer these please?
please explain 34 and in 35 the answer is A i dont get how reaction 3 is disproportionation reaction.. :/ in my book only reaction 1 and 2 are given. :S

 

[gary221]

can u answer these please?
please explain 34 and in 35 the answer is A i dont get how reaction 3 is disproportionation reaction.. :/ in my book only reaction 1 and 2 are given. :S

For 34, the ans is D..ie 1 only..
bcoz Ca(OH)2 is slightly soluble in water n Ba(OH)2 is more soluble..so only Ca will form a white ppt ...but Ba will not
P.S. Both Ca n Ba form alkaline hydroxides n give off a gas..Hydrogen

 

[mominzahid]

For 34, the ans is D..ie 1 only..
bcoz Ca(OH)2 is slightly soluble in water n Ba(OH)2 is more soluble..so only Ca will form a white ppt ...but Ba will not
P.S. Both Ca n Ba form alkaline hydroxides n give off a gas..Hydrogen

Thanks.. and 35?

 

[gary221]

can u answer these please?
please explain 34 and in 35 the answer is A i dont get how reaction 3 is disproportionation reaction.. :/ in my book only reaction 1 and 2 are given. :S

For 35, the ans is A..
the complete eqn for the 3rd reaction is 3NO2 + H2O = NO + 2HNO3
Here N is getting oxidised as well as reduced... 1st its oxidation no is +4... in NO, it is +2 (hence it is reduced)
n in HNO3, it is +5 (it is oxidised)
Hope u gt it!!

 

[mominzahid]

In 34, we know that group II metals react with cold water, forming a hydroxide, which is alkaline. It is also basic concept that addition of a group two metal to cold water would liberate hydrogen. A white suspension only appears when Calcium is added, since calcium hydroxide is not soluble. So answer should be D, I think.

In 35, you have to complete the equations first. The question itself states that the equations are incomplete.
In the first equation you'll get a chlorate anion in the products.
So then you can easily see that chlorine has been oxidized as well as reduced. Hence 1 has to be a disproportionation reaction
In the 2nd one, on completion of the reaction you'll get a chlorine anion in the products, and yet again it has been oxidized and reduced, hence disporpotionation.

For 35, the ans is A..
the complete eqn for the 3rd reaction is 3NO2 + H2O = NO + 2HNO3
Here N is getting oxidised as well as reduced... 1st its oxidation no is +4... in NO, it is +2 (hence it is reduced)
n in HNO3, it is +5 (it is oxidised)
Hope u gt it!!

In the 3rd one, you'll get HNO2 in the products, hence, nitrogen has been oxidised and reduced, again a disproportionation. Hence, answer is A

Ahhhh... Thanks ALOTTTT... THat was easy.. lol..
Thanks a bunch guyss.I alot more questions i'll post em here.. you are the best.

 

[mominzahid]

Okay guys 4 questions i dont get.. please help if you can.. thanks..

 

[Student12]

12 Camphor is a white solid which was used to make the early plastic celluloid. Camphor contains
the same percentage by mass of hydrogen and oxygen.
What is the molecular formula of camphor?
A C10H6O6 B C10H8O C C10H16O D C10H10O2

How is it C ?

Someone please answer my Questions at the previous page & this 1 too!

 

[saudha]

12 Camphor is a white solid which was used to make the early plastic celluloid. Camphor contains
the same percentage by mass of hydrogen and oxygen.
What is the molecular formula of camphor?
A C10H6O6 B C10H8O C C10H16O D C10H10O2

How is it C ?

Someone please answer my Questions at the previous page & this 1 too!

maybe because... h-16 and mass of oxygen (if u check in the periodic table) is 16 (mass) so they have equal masses ...i mole of O and 16 H
im nt sure though

 

[Student12]

maybe because... h-16 and mass of oxygen (if u check in the periodic table) is 16 (mass) so they have equal masses ...i mole of O and 16 H
im nt sure though

i thought like that too.. but not sure if thats how i should be thinking

 

[leosco1995]

12 Camphor is a white solid which was used to make the early plastic celluloid. Camphor contains
the same percentage by mass of hydrogen and oxygen.
What is the molecular formula of camphor?
A C10H6O6 B C10H8O C C10H16O D C10H10O2

How is it C ?

Someone please answer my Questions at the previous page & this 1 too!

Same % mass means the same amount of mass of hydrogen and oxygen, so you have 16 Hydrogens and 1 oxygen atom. It's actually a simple question.

 

[leosco1995]

The products obtained by cracking an alkane, X, are methane, ethene and propene.
The mole fraction of ethene in the products is 0.5.

What is the identity of X?

A C6H14 B C8H18 C C9H20 D C11H24

 

[freezingfires]

 

[umarashraf]

to make the alcohal a chiral one as well we can use minimum 7 Carbons....


CH3
!
C2H5 -C-OH
!
C3H7

these are six Carbons.... hope you understood mate...

 

[umarashraf]

 

[i love my country]

hi this is the first time that i post any thing on xtreme but i have a question can some one explain for me why question 11 m\j 2010 variant 12 is A because im confused

I HOPE GOOD LUCK FOR ALL OF U GUYS and THANKS...