chemistry p1 help!! plz.

[Amanina]

what is SN1 and SN2?

for example, in question ON09 variant 2 no. 36?

can anyone explain to me and others?

 

[beacon_of_light]

what is SN1 and SN2?

for example, in question ON09 variant 2 no. 36?

can anyone explain to me and others?

SN1 and SN2 are two different mechanisms of nucleophilic substitution...

A few points to remember!

.

SN1 SN2

two step reaction single step reaction

1 molecule involved in rate determination step(RDS) two molecules involved in RDS

occurs in secondary and tertiary haloalkanes occurs in sec. and primary haloalkanes

nucleophile attacks from same side of leaving nucleophile Nuc. attacks from opposite side of leaving nucleophile

No pentavalent specie (carbocation formed) intermediate with Carbon having 5 bonds(pentavalent shape)

polar solvent required non polar solvent required


For full mechanism see Longman chemistry!!!

Hope that helps u

 

[Amanina]

@ beacon_of_light

thanks for the explanation. yea, i'll look through longman after this.

 

[paparazzi]

Sorry.a lot of qs again..my chem sucks.
mj 06. QS 6,26,28,32

 

[beacon_of_light]

Sorry.a lot of qs again..my chem sucks.
mj 06. QS 6,26,28,32

q6: An ideal gas has no forces of attraction...while here ammonia has hydrogen bonding b/w its molecules which means strong forces exist and it therefore does not resemble an ideal gas...

q26: answer is Na...only Na would react with alcohol///Br would react with alkenes , KMnO4 would oxidise alcohol + alkenes while 2,4 DNPH is totally out of the the choices!

q28: during this reaction, ketone group would react with DNPH while ester group wouldn't....so in D it does...for further explanation consult a gud book...

q32: now firstly Na (s) would be converted to Na (g)...that is enthalpy change of atomisation...then Na(g) to Na+(g)..and obviously that is first ionisation energy,,,so B is the correct choice...

Hope u gt that!

 

[paparazzi]

mj 08
Q 26,27,28,40???
Any one? plz

 

[beacon_of_light]

mj 08
Q 26,27,28,40???
Any one? plz

q26: Since the question says that the alcohol has two OH...so in total two oxygen atoms...and after oxidation ..Oxygen atoms increase to 4..means there would be 2 COOH groups in the final product...And as you know the alcohol must be a primary one so that its final product of oxidation is a dicarboxylic acid...so OH must be attached to C atom 1 and 4...to make a primary alcohol!!!

q27: tertiary alcohols donot undergo oxidation..it means before dehydration the alcohol must be a tertiary one..and in Option D if you add OH and H to the double bond, you'll get a tertiary alcohol...the rest give secondary alcohols...

q28: All aldehydes undergo nucleophilic addition reactions...which means a nucleophile attacks the carbon of carbonyl group...here option C reflects the answer!

q40: the molecul contains a double bond so HBr and KMnO4 can react with this molecule while it contains NaOH which will react with acidic group COOH!!!

GOT THAt??

 

[paparazzi]

mj 08
Q 26,27,28,40???
Any one? plz

q26: Since the question says that the alcohol has two OH...so in total two oxygen atoms...and after oxidation ..Oxygen atoms increase to 4..means there would be 2 COOH groups in the final product...And as you know the alcohol must be a primary one so that its final product of oxidation is a dicarboxylic acid...so OH must be attached to C atom 1 and 4...to make a primary alcohol!!!

q27: tertiary alcohols donot undergo oxidation..it means before dehydration the alcohol must be a tertiary one..and in Option D if you add OH and H to the double bond, you'll get a tertiary alcohol...the rest give secondary alcohols...

q28: All aldehydes undergo nucleophilic addition reactions...which means a nucleophile attacks the carbon of carbonyl group...here option C reflects the answer!

q40: the molecul contains a double bond so HBr and KMnO4 can react with this molecule while it contains NaOH which will react with acidic group COOH!!!

GOT THAt??

yeah. thx again.