Chemistry: Post your doubts here!

[nehaoscar]

Why is 1 wrong?
Will the pressure be equal??

 

[Studydayandnight]

How do we solve this

Correct answer is A.

Question is: Which process could be used to calculate the bond energy for the covalent bond X-Y by dividing its Delta H by n?

 

[nehaoscar]

Help! it's 1 and 2 only
How would each react and what will it give in each case? And what would 3 give since it's wrong??

 

[princess Anu]

help

 

[Falconwing]

How +2??

2 moles of metallic salt react with 1 mole of sodium sulfite, oxidising sulfite needs 2 electrons. So, the original oxidation number of metal is +3, and there are two moles, so the new oxidation will be +2.

Reaction of aldehydes with HCN require Reflux OR it occurs at RTP?

RTP apparently

Help Please!!!
Use of the Data Booklet is relevant to this question. Sir Humphrey Davy discovered boron, calcium, magnesium and sodium. Which of these elements has the second smallest atomic radius in its group and the third lowest first ionisation energy in its period?
A boron
B calcium
C magnesium
D sodium

The Ans is C

Magnesium is second in it's group, so it would have the second smallest radius (because of more electron shells) and it has the third lowest ionisation after sodium and aluminium.. IE increases across the period, but Aluminium has an outer p subshell so it's IE is lower ^^

 

[The Sarcastic Retard]

How do we solve this

Correct answer is A.

Question is: Which process could be used to calculate the bond energy for the covalent bond X-Y by dividing its Delta H by n?

Let x = C, y = H and n = 4
Now tell me isn't A the correct option?

 

[awesomaholic101]

But If you count again you will find out that there are 8 tertiary carbon atoms !!
Try

oh i think i realised ur mistake ... u are counting both Carbon atoms in two of the C=C double bond ... i don't think we should do that ...

 

[awesomaholic101]

Reaction of aldehydes with HCN require Reflux OR it occurs at RTP?

KCN (or in some questions, they give NaCN) is used as catalyst

 

[awesomaholic101]

View attachment 54837
Do alkenes not react with NaBH4??

As far as i know, in our syllabus ... NaBH4 is only used to reduce aldehydes ...

 

[awesomaholic101]

View attachment 54836
What would A give? why is A wrong?

KCN is used for the nucleophilic substitution of halegenoalkane with CN- ions ... not HCN

 

[BhaiArshad]

???

 

[awesomaholic101]

???

D?

 

[Falconwing]

???

Is the answer D? A redox reaction surely doesn't occur, and Ammonia won't act as a base because there is nothing to neutralise...

 

[BhaiArshad]

D?

Is the answer D? A redox reaction surely doesn't occur, and Ammonia won't act as a base because there is nothing to neutralise...

Yes but plz explain

 

[nehaoscar]

KCN is used for the nucleophilic substitution of halegenoalkane with CN- ions ... not HCN

But then would HCN give a different product?
it will just form HBr instead of KBr right?
And suppose we said that happened then what would the HCl do? It will also form an acidic hydrolysis - COOH??

 

[nehaoscar]

Why is 1 wrong?
Will the pressure be equal?

 

[nehaoscar]

Help! it's 1 and 2 only
How would each react and what will it give in each case? And what would 3 give since it's wrong??

 

[BhaiArshad]

All will make aldehyde or carboxylic acid but which one is the one with low BP?

 

[BhaiArshad]

Why not B?
Answer is C

 

[goldenkatana]

uhm ... option 3 is wrong because the initial reactant isn't an ester ... only esters have this alkaline hydrolysis thingy to produce salt of acid ... nd 2nd option, i've never come accross it ... first is right coz the O-H bond will break and Na will take the place of hydrogen ...
but i am not sure ... if you know which year the paper is, plz do check the ms and lemme kno ...

But according to
http://www.chemguide.co.uk/organicprops/acids/acidity.html
It can react with all the three?