IGCSE/GCSE/O & A Level/IB/University Student Forum

Qualification => Subject Doubts => GCE AS & A2 Level => Sciences => Topic started by: Aymen Ezazi on May 14, 2013, 10:42:31 am

Title: Chemistry
Post by: Aymen Ezazi on May 14, 2013, 10:42:31 am

hey all.. i am new to this forum, and doing past papers so lots of doubts coming up!!
can anyone explain me question 5 in paper 1.. why the answer is B and not D?? the hydrogen bonds are broken in methane because it is broken down to carbon and hydrogen.. not in ammonia bcoz its just changing to gas..http://papers.xtremepapers.com/CIE/Cambridge%20International%20A%20and%20AS%20Level/Chemistry%20(9701)/9701_s06_qp_1.pdf .. this is the link to the paper!!

Title: Re: Chemistry
Post by: Suryaw1 on May 28, 2013, 05:57:51 pm

Hydrogen bonds are only formed when hydrogen is bonded to very electronegative elements, such as N, O and F. In question no 5, only option B has hydrogen bonds. Therefore it also can be broken down.

Title: Re: Chemistry
Post by: NotAbod on May 28, 2013, 06:02:31 pm

Quote from: Suryaw1 on May 28, 2013, 05:57:51 pm

Hydrogen bonds are only formed when hydrogen is bonded to very electronegative elements, such as N, O and F. In question no 5, only option B has hydrogen bonds. Therefore it also can be broken down.

Indeed. This is correct.
Thanks for answering him :)