Chemistry MCQ thread...

[Zishi]

Which of the following statements regarding the chlorides MgCl2, SiCl4 and PCl3 is
correct?
A All three chlorides hydrolyse completely in water to give acidic solution.
B The oxidation states of chlorine in the three chlorides are –2, –4 and –3 respectively.
C All are liquids at room temperature.
D MgCl2 is the only chloride having a giant structure.

D

 

[diwash]

@ hassam
1st Q is ...C (enthalpy change)
2nd Q is ....D (Ice)
3rd Q is.....C (naI and NaCL)
4th Q is...D ( chlorides)

Are the answers correct?

 

[hassam]

D

ITS B !!!

 

[hassam]

OTHERS ARE CORRECT ZISHI

 

[ninjas4life]

 

[hassam]

B...1 and 2 correct,,,u write down equations...nd then u ll see why its not 3

 

[Hateexams93]

whats wrong with the answers :/?

can some1 help me ?

 

[Zishi]

D

ITS B !!!

I think B says that bond angles about oxygen are 109.5 degree, which is absolutely correct...This is ice, it has 2 H bonds, with other H2O molecules and 2 covalent bonds between itself. This means that it has to have a tetrahedral arrangement.See this: http://sg.answers.yahoo.com/question/in ... 213AAPiH8j

It has bond angle of 109.5, book is wrong.

 

[diwash]

@ hateexam...Answer is D....It is because Oxidising power decreases down the group 7 as a result the Iodine is less oxidising than Sulphuric acid.

 

[ideggkr]

Hey guys.
This is the question uploaded by hassam some time ago.

I think u implied that the answer is C

I get it solid is not taken into account when getting Kc

But why is water ignored?

In all other examples, water is taken into account. And I did so in p22 as well.

Help?

 

[Banglarbagh]

bro hw r u postin the images here, i mean wch tools r u usin may i kno please.!

 

[ideggkr]

just press 'print screen' and then
open ur paint and 'ctrl + v'
then crop ur image using dotty rectangle
and then save the cropped part as a new image
change the extension (bit) to sth else like jpg or jpeg

this is how i do n it's damn simple if u do several times

 

[Xthegreat]

Hey guys.
This is the question uploaded by hassam some time ago.

I think u implied that the answer is C

I get it solid is not taken into account when getting Kc

But why is water ignored?

In all other examples, water is taken into account. And I did so in p22 as well.

Help?

pure water has no concentration?

 

[Banglarbagh]

hw do i pst it here..????

 

[ideggkr]

Hey guys.
This is the question uploaded by hassam some time ago.

I think u implied that the answer is C

I get it solid is not taken into account when getting Kc

But why is water ignored?

In all other examples, water is taken into account. And I did so in p22 as well.

Help?

pure water has no concentration?

well then why in all other examples in textbooks etc, they consider H2O as well?

are they contaminated water or sth lol..

 

[Zishi]

Hey guys.
This is the question uploaded by hassam some time ago.

I think u implied that the answer is C

I get it solid is not taken into account when getting Kc

But why is water ignored?

In all other examples, water is taken into account. And I did so in p22 as well.

Help?

pure water has no concentration?

well then why in all other examples in textbooks etc, they consider H2O as well?

are they contaminated water or sth lol..

No that's not the thing. Water is in excess, so it's constant, and we mostly ignore it while using Kc.

 

[ideggkr]

Oh! Thanks. That's why we don't ignore it when H2O is a product cuz it's not in excess.

 

[TITTIITT]

I thought there is CO+ (1/2)O2 = CO2 so I chose A but the answer is C?

 

[Banglarbagh]

hw do i post the images in dis forum pls tell me..!!

 

[Xthegreat]

I thought there is CO+ (1/2)O2 = CO2 so I chose A but the answer is C?

according to what my lecturer found, CO has a very very very long half-life and cannot be oxidise easily.

thats why.