Chemistry: Post your doubts here!

[angelgirl:)]

m/j 2010 Q no.11...y cant the anser be B insted of A?

 

[Amaryllis]

it cant be B because atoms CAN be split into subatomic particles.. (remmeber frm physics )
C
Q26..
it has to be a tertiary alcohol as it doesn't react wid MnO4- ..... chiral carbon so we need three differnt groups... (the general formula shows dat there are no C+C either)
draw it out n u'll see the best way will be to have a central C wid one -OH grp, one methyl, one ethyl and one propyl grp attatched... thus 7 atoms required

thank you so much... but why in Q 12 its B ,i always know that ALCL3 is the compound that can act as ionic and covalent

 

[saudha]

the qs is not clear angelgirl...

 

[étudiante]

thank you so much... but why in Q 12 its B ,i always know that ALCL3 is the compound that can act as ionic and covalent

ur welcum
yes! it IS AlCl3 that acts as ionic and covalent... i think i wrote C dere... or must b a typos >.< sorry...

 

[Amaryllis]

ur welcum
yes! it IS AlCl3 that acts as ionic and covalent... i think i wrote C dere... or must b a typos >.< sorry...

thanks and good luck in your exam

 

[angelgirl:)]

the qs is not clear angelgirl...

m/j 2010

 

[étudiante]

thanks and good luck in your exam

ur welcome same to u 2

 

[saudha]

ok

m/j 2010 Q no.11...y cant the anser be B insted of A?

for this q ... i dont noe why A is the answer but B cannot be as if u ass chloride ions ..... it needs a supply of oxygen and cannot form ClO- ion

 

[angelgirl:)]

m/j 2010

m/j 2010 Q NO,11

 

[hmlahori]

can someone explain how NO2 is polar?
the electronegativities of N and O are different so the bonds will be polar but wont the dipoles cancel each other out and the overall compound becomes nonpolar.

 

[étudiante]

can someone explain how NO2 is polar?
the electronegativities of N and O are different so the bonds will be polar but wont the dipoles cancel each other out and the overall compound becomes nonpolar.

the bond angle is not 180 (because of the lone pair on nitrogen) thus it will be cancelled to some extent but not completely and will overall be polar

 

[hmlahori]

the bond angle is not 180 (because of the lone pair on nitrogen) thus it will be cancelled to some extent but not completely and will overall be polar

does the shape of a molecule affect the overall polarity of a compound to a large extent then?

 

[étudiante]

does the shape of a molecule affect the overall polarity of a compound to a large extent then?

yes! dipoles are vectors so if u want them to completely cancel, u need to take into account direction as well... (i.e. shape)

 

[hmlahori]

yes! dipoles are vectors so if u want them to completely cancel, u need to take into account direction as well... (i.e. shape)

Ok rite yes i just drew the NO2 molecule and i get what you mean. Its nitrogen part will be partial positive and two oxygen atoms partial negative so it is polar just like in H2O and as they are both bent so dipoles wont completely cancel out. Thanks a lot!

 

[étudiante]

Ok rite yes i just drew the NO2 molecule and i get what you mean. Its nitrogen part will be partial positive and two oxygen atoms partial negative so it is polar just like in H2O and as they are both bent so dipoles wont completely cancel out. Thanks a lot!

exactly! ur welcome
except that the bond angle will be different frm H2O its da same concept

 

[hmlahori]

exactly! ur welcome
except that the bond angle will be different frm H2O its da same concept

yes yes i know because there are 2 lone pairs in H2O and one in NO2. but you know i never really considered the shape but now these questions will be easier to solve thanks again!

 

[saudha]

Which ion is most polarising?
A Al3+
B Ba2+
C Mg2+
D Na+

wht do u mean by pol arising?

 

[étudiante]

yes yes i know because there are 2 lone pairs in H2O and one in NO2. but you know i never really considered the shape but now these questions will be easier to solve thanks again!

yep! ^_^
ur so welcum... just remember me in ur prayers pls

 

[1357913579]

can you guys please also clear my doubts which i posted in the AS chemistry forum i would be very thankfull of you please help

 

[étudiante]

Which ion is most polarising?
A Al3+
B Ba2+
C Mg2+
D Na+

wht do u mean by pol arising?

the one dat can distort the charge cloud of the anion the most....
it will be the one with the greatest charge denstiy (i.e. smallest radius and highest charge)