Chemistry: Post your doubts here!

[Zaki ali asghar]

Need help with a Q5 (c) from Oct/Nov 2017 paper 41View attachment 63581 View attachment 63582
Why is there no addition of HCl with the double bond?

for that you need concentrated hcl and at rtp

 

[Hajera]

for that you need concentrated hcl and at rtp

but look at the 1st row. when excess Br2 (aq) is reacted with the molecule, addition does occur. even though they didnt mention whether it is conc or at rtp.

 

[Hajera]

also in this question, why doesnt Br2 react with the double bond?

 

[Krypton36]

Anybody got 9701_m18_qp_42 yet?????

 

[ujjwal jha]

there is no reaction possibly of acid with alkene. please check!

 

[aermoid]

if u have 9701_m18_qp_42 plz share

 

[Zaki ali asghar]

 

[ujjwal jha]

here, from the spectra we can see there are 4 different carbon environment. so in isomer " R" there are 5 different carbon environment. while in isomer "S" there is only 3 carbon environment. as in isomer " T " there are four environment. hence it is spectra of isomer T

 

[PixelsLevls]

there is no reaction possibly of acid with alkene. please check!

There is definitely a reaction with Hydrogen Halides, and they are also acids. HCl reacts with Alkenes in gaseous state or mixed in water as a concentrated solution, which is basically hydrochloric acid. This is because the hydrogen will act as a electrophile, as it already has a slightly positive charge due to the electronegative chloride ion.

 

[ujjwal jha]

sorry , i had misunderstood your question

 

[haithsoul]

how was chemistry paper 4, 42 guys?

 

[Zaki ali asghar]

Quite good, was easier than the last year.

 

[Metanoia]

View attachment 63545
How do we come to know where to place the Cl and NH3? Cant there be any other arrangement apart from these?
View attachment 63546

There are only 2 unique ways to place the 2 Cl atoms, either 180 degrees from each other or 90 degrees

 

[haithsoul]

Quite good, was easier than the last year.

yeah its was, lets discuss what was the ph? for first question?

 

[Zaki ali asghar]

1.6

 

[Zaki ali asghar]

Temperature was 2836 and volume 448cm^3

 

[haithsoul]

Temperature was 2836 and volume 448cm^3

yes i have same temperature and volume but different ph. how did you get 1.6 mine was alot higher

 

[Zaki ali asghar]

after finding the moles you had to calculate the conc using n*1000/800 and then the ph formula

 

[haithsoul]

Temperature was 2836 and volume 448cm^3

how did you find the concentration for the OH?

 

[haithsoul]

after finding the moles you had to calculate the conc using n*1000/800 and then the ph formula

btw how many proton peaks with there be?