Chemistry MCQ thread...

[MHHaider707]

What exactly do they mean by NEIGHBOURS? shouldn't it in a normal way mean any atom next to it (up, down, left and right)?....In that cause B shouldn't be the answer (as Boron's second IE is greater than that of aluminium)

Answer is B!!!

Its electronic configuration of of Al which will have the highest ionization energy than its neighbors!!!

I think neighbors mean the elements at left and right in periodic table!!

 

[Anonymousx3]

What exactly do they mean by NEIGHBOURS? shouldn't it in a normal way mean any atom next to it (up, down, left and right)?....In that cause B shouldn't be the answer (as Boron's second IE is greater than that of aluminium)

The question means that the IE has to be higher than both the element that comes before it and the element that comes after it.
In this case, the answer is B.
Al has a second IE of 1820, higher than the element before it (Mg - 1450) and higher than the element after it (Si - 1580).
I hope that cleared it up for you.

 

[xHazeMx]

What exactly do they mean by NEIGHBOURS? shouldn't it in a normal way mean any atom next to it (up, down, left and right)?....In that cause B shouldn't be the answer (as Boron's second IE is greater than that of aluminium)

we dont take the elements above and down each element right? .. only left and right ??

 

[Anonymousx3]

What exactly do they mean by NEIGHBOURS? shouldn't it in a normal way mean any atom next to it (up, down, left and right)?....In that cause B shouldn't be the answer (as Boron's second IE is greater than that of aluminium)

we dont take the elements above and down each element right? .. only left and right ??

No, just left and right.
If you think about the definition, a neighbour is usually someone who lives next-door to another (to the left or right), not on top or below. ;p

 

[xHazeMx]

hahaha, MAKES SENSE NOW !

 

[MHHaider707]

Hey can anyone tell me about Q. 7 , 9 , 38 of O/N 04 P1

http://www.xtremepapers.me/CIE/Internat ... 4_qp_1.pdf

 

[hassam]

Which of the following has the smallest bond angle?
A H2S
B SCl2
C BCl4−
D NO3-

 

[xHazeMx]

Hey can anyone tell me about Q. 7 , 9 , 38 of O/N 04 P1

http://www.xtremepapers.me/CIE/Internat ... 4_qp_1.pdf

Q 7 was removed from the exam as P has a lone pair so the angle should be 107 which is not given in the choices, though they have given the answer as D which makes no sense due to the presence of a lone pair in the P atom
correct me if i m wrong

 

[sakibfaiyaz]

What exactly do they mean by NEIGHBOURS? shouldn't it in a normal way mean any atom next to it (up, down, left and right)?....In that cause B shouldn't be the answer (as Boron's second IE is greater than that of aluminium)

The question means that the IE has to be higher than both the element that comes before it and the element that comes after it.
In this case, the answer is B.
Al has a second IE of 1820, higher than the element before it (Mg - 1450) and higher than the element after it (Si - 1580).
I hope that cleared it up for you.

So I don't take elements above and below it? :S
LOL, CIE's english is really Scottish :S

 

[xHazeMx]

Which of the following has the smallest bond angle?
A H2S
B SCl2
C BCl4−
D NO3-

is it A ?

 

[MHHaider707]

Yeah, there should be a choice of 107*...

wat abt Q. 9 and 38??

 

[MHHaider707]

Which of the following has the smallest bond angle?
A H2S
B SCl2
C BCl4−
D NO3-

I think its B!!

 

[Zishi]

Which of the following has the smallest bond angle?
A H2S
B SCl2
C BCl4−
D NO3-

A?

 

[Anonymousx3]

Hey can anyone tell me about Q. 7 , 9 , 38 of O/N 04 P1

http://www.xtremepapers.me/CIE/Internat ... 4_qp_1.pdf

Q9 - The choices we've been given are propane and 3 of its oxidation products. Every stage in the oxidation process will be exothermic, and therefore the earliest point in a sequence of oxidations will yield the highest energy release. The answer is B - propane. Or you could also use the bond energies in the data booklet.

Q 38 - The answer is A. 1 is correct because there's twice the number of chlorine atoms (than in CH3CH2Cl). 2 and 3 are also correct because the carbon-halogen bond (C-Br and C-I) undergoes heterolytic fission more readily (lower bond energies - the bonds become easier to break).

 

[sakibfaiyaz]

Hey can anyone tell me about Q. 7 , 9 , 38 of O/N 04 P1

http://www.xtremepapers.me/CIE/Internat ... 4_qp_1.pdf

38 should be A. 1 has 2 Cl substituents hence faster rate...and both 2 and 3 will have a faster rate as the bond enthalpy of C-Br and C-I is less than C-Cl....
NOTE: the graph doesnt level out, indicating the reaction completes much later.......at the end point the original curve, 2 and 3 will be at the same level and 1 will be at a higher level.
Hope this helps

 

[xHazeMx]

answer this with explanation

 

[MHHaider707]

Hey can anyone tell me about Q. 7 , 9 , 38 of O/N 04 P1

http://www.xtremepapers.me/CIE/Internat ... 4_qp_1.pdf

Q9 - The choices we've been given are propane and 3 of its oxidation products. Every stage in the oxidation process will be exothermic, and therefore the earliest point in a sequence of oxidations will yield the highest energy release. The answer is B - propane. Or you could also use the bond energies in the data booklet.

Q 38 - The answer is A. 1 is correct because there's twice the number of chlorine atoms (than in CH3CH2Cl). 2 and 3 are also correct because the carbon-halogen bond (C-Br and C-I) undergoes heterolytic fission more readily (lower bond energies - the bonds become easier to break).

Thanx but i didn't get abt Q.9 . . . still confused :%)

 

[MHHaider707]

Hey can anyone tell me about Q. 7 , 9 , 38 of O/N 04 P1

http://www.xtremepapers.me/CIE/Internat ... 4_qp_1.pdf

38 should be A. 1 has 2 Cl substituents hence faster rate...and both 2 and 3 will have a faster rate as the bond enthalpy of C-Br and C-I is less than C-Cl....
NOTE: the graph doesnt level out, indicating the reaction completes much later.......at the end point the original curve, 2 and 3 will be at the same level and 1 will be at a higher level.
Hope this helps

Yeah thanx it really helped!!

 

[Xthegreat]

answer this with explanation

whats the ans? B?

 

[Xthegreat]

yeah, the answer is B, i just checked.

C-H bonds releases the most energy, hence B ( alkane ) has the most C-H bonds.