Chemistry MCQ thread...

[ShootingStar]

Question!
Please explain

for question 9,

the answer is D

if in SO3 (Charge : -2) the oxidation number is +3.... when it changes into SO4 (still -2) there is an extra -2 charge due to the additional oxygen ion, but the final charge still remains (-2). So the Sulphur ion must've balanced the extra (-2) . So it must have +5 charge

The answer is B for question 9 and question 10 is D. Can you please explain how to work it out?

 

[Vanto1994]

Answer is D! Where are the 6 chiral carbons ?!?!

 

[kshumaila52]

Question!
Please explain

Q9. find mole of each (metallic salt=.005, mole of sulfate=.0025)
compare molar ratio ( i mole of sulpfate reduces 2 mole of metallic salt)
one mole of sulfate loose 2 electrons, so one mole of metal gain 1 electron( 2 mole gain 2 electron)
if original was 3, then gain of 1e will be 2
Q10. i just explain a question like this...
1st initial moles, then after reaction, put values and get ans.

 

[aleem420]

What is the total number of different chloroethanes, formula C2H6-nCln, where n can be any
integer from 1 to 4?
A 4
B 6
C 7
D 8

 

[xHazeMx]

Answer is D! Where are the 6 chiral carbons ?!?!

these are the chiral centres

 

[aleem420]

What is the total number of different chloroethanes, formula C2H6-nCln, where n can be any
integer from 1 to 4?
A 4
B 6
C 7
D 8



Plz help me............

 

[ShootingStar]

Question!
Please explain

Q9. find mole of each (metallic salt=.005, mole of sulfate=.0025)
compare molar ratio ( i mole of sulpfate reduces 2 mole of metallic salt)
one mole of sulfate loose 2 electrons, so one mole of metal gain 1 electron( 2 mole gain 2 electron)
if original was 3, then gain of 1e will be 2
Q10. i just explain a question like this...
1st initial moles, then after reaction, put values and get ans.

uh..i didn't quite understand your explanation to Q9 .. :unknown:

 

[Aloo007]

@ aleem is the ans 7?

 

[Octahedral]

How do i insert a screenshot for a question?

 

[aleem420]

@ aleem is the ans 7?

yes it is but how???????????????????

 

[xHazeMx]

.

 

[ShootingStar]

How do i insert a screenshot for a question?

On Adobe where you opened the question paper, on the toolbar, go to Tools -> Select and Zoom -> Snapshot tool.
Select the area you want and paste it on paint and save it.
When posting the question on XPF, click on Upload attachment, then choose file then select the file you saved earlier.

 

[Octahedral]

Thx

 

[Saturation]

.

A?

 

[xHazeMx]

.

A?

No

 

[histephenson007]

isin't the answer A?

cause from what i know, chlorine is a stronger oxidising agent than sulphuric acid.

yea right!

 

[ShootingStar]

.

D? because tertiary haloalkanes can only undergo SN1 reactions

 

[histephenson007]

.

D...tertiary .... the CI almost looks like chlorine

 

[Aloo007]

@ aleem just draw the molecoule of CH3CH3 and then start adding cl and removing H one by one im new at this site so i dont know how to insert a screenshot but ill tell u one by one
1. one cl on carbon 1
2. two cl on carbn 1
3. three cl on carbon 1
4. three cl on carbon 1 and one cl on carbon 2
NOW STRUCTURAL ISOMERS
5. one cl on each carbon
6. two cl on carbon 1 and one cl on carbon 2
7. two cl on each carbon

 

[sweetiepie]

DOES ANYONE HAS PAPERS B4 2002 PLZZ IF U HAV CAN U SEND MEE......