A2 Chemistry P5

[Xenon]

I need help with this is part of question 1 from oct/nov 2007. I will like to know whether the enthalpy of solution will decrease or increase in magnitude and why:

 

[Sweet_angel]

it decreases from LiOH to CsOH

 

[Xenon]

it decreases from LiOH to CsOH

Can u please explain why it decreases.
Thanks

 

[soumayya]

As we move down Group I hydroxides, the bases become more soluble since the ^H soln becomes more exothermic...this is because of an increase in ionic radii of the cations from Li to Cs....

hope that helps...

 

[Xenon]

^H soln becomes more exothermic..

If ^H soln becomes more exothermic the magnitude should increase. right?
But the mark scheme says decrease

 

[soumayya]

When ^Hsoln becomes more exothermic, this means that it becomes more negative...that is, it decrease..

 

[Xenon]

When ^Hsoln becomes more exothermic, this means that it becomes more negative...that is, it decrease..

thanks

 

[soumayya]

u're welcome..