Lurkers, register with SgForums and ask ur H2 Chem qns here!

• Flying grenade

  26 May 16, 16:20

  Originally posted by UltimaOnline:

  
  Bronsted-Lowry acidification or protonation.

  Thanks !!!

• Flying grenade

  26 May 16, 22:57

  What does proticity mean? Can't find the meaning online

   

  Is it mean how many H it can donate?

   

  U.O. told me that formula of salt formed is based on proticity, based on the discussion of george chong's inorganic book having a error at page 40

• Flying grenade

  26 May 16, 23:25

  [IGNORE this epic fail post. Found my mistake, written below]

  Omg wtf, ultima hope u can help on this

  Page 40 george chong's inorganic book

   

  Oxides of phosphorus with alkalis : 

  (After making corrections) product when p4o6 react with NaOH is Na2HPO3 . I calculated o.s. of P is +3 (can help check?)

  Product when p4o10 react with NaOH is Na3PO4. I calculated  o.s. of P is +5 (can help check? )

   

   

   

  !? Wait. Update : for george chong's inorganic book, i have serious anomalous results compared to his writing 

   

  On both pages 40 and 41, specifically Oxides of P and oxides of S parts , he wrote Four times, that when oxides dissolve in water/neutralised by alkalis , oxidn number/state do not change ! Neutralisation, dissociation are not redox reactions

   

  But I've calculated o.s. if all the P and S compounds in page 40 and 41, the o.s. aren't the same(e.g. the top portion of this post) !!!

  Please please help !!

   

• Flying grenade

  26 May 16, 23:47

  Shit la. Actually i think i made a serious blunder 

  He meant o.s. of p in p4o10 and os in na3po4 is the same, +5. SOOORRRRYRYYY !!

• UltimaOnline

  27 May 16, 01:01

  Originally posted by Flying grenade:

  What does proticity mean? Can't find the meaning online

   

  Is it mean how many H it can donate?

   

  U.O. told me that formula of salt formed is based on proticity, based on the discussion of george chong's inorganic book having a error at page 40

  
  Proticity refers to how many protons a Bronsted-Lowry acid can donate, or how many protons a Bronsted-Lowry base can accept. Eg. H3PO4 is a triprotic acid, hence PO4 3- is a triprotic base.

  Since H3PO3 (Latin name phosphorous acid, Stock name phosphoric(III) acid, IUPAC name phosphonic acid) is a diprotic acid, hence upon complete deprotonation using excess NaOH(aq) in a Bronsted-Lowry acid-base reaction, the salt generated is Na2HPO3 (Latin name disodium phosphite, Stock name disodium phosphate(III), IUPAC name disodium phosphonate).

• Flying grenade

  27 May 16, 07:14

  Thanks alot !!

• Flying grenade

  27 May 16, 12:36

  Is it possible to synthesise methanal ? As it will further oxidise to co2 and h2o 

   

  Use methanol, k2cr2o7, heat with immediate distillation, can get methanal?

• Flying grenade

  27 May 16, 12:52

  Hi Ultima, hope you can help me, please !

  https://www.dropbox.com/s/5kz1e3dc81gswep/20160527_125045-1.jpg?dl=0

• UltimaOnline

  27 May 16, 13:09

  Originally posted by Flying grenade:

  Is it possible to synthesise methanal ? As it will further oxidise to co2 and h2o 

   

  Use methanol, k2cr2o7, heat with immediate distillation, can get methanal?

  
  Obviously methanal can be synthesized.

  https://en.wikipedia.org/wiki/Formaldehyde#Industry

  Using methods within H2 syllabus will have very low yield. Cambridge will understand this and either not ask, or will accept the within-syllabus method, etc.

• UltimaOnline

  27 May 16, 13:10

  Originally posted by Flying grenade:

  Hi Ultima, hope you can help me, please !

  https://www.dropbox.com/s/5kz1e3dc81gswep/20160527_125045-1.jpg?dl=0

  
  This problem you need to ask your school teacher or private tutor face-to-face, because it's not a simple balancing of equation using molecular formulae, as it involves molecular structures and mechanisms, cannot efficiently settle on forum.
• Flying grenade

  27 May 16, 15:37

  Originally posted by UltimaOnline:

  
  This problem you need to ask your school teacher or private tutor face-to-face, because it's not a simple balancing of equation using molecular formulae, as it involves molecular structures and mechanisms, cannot efficiently settle on forum.

  Ultima, can help me check my answers and teacher's answer at the left column? For the 2nd product, i thought its methanoic acid, but my cher say it's co2, idk why

• UltimaOnline

  27 May 16, 16:31

  Originally posted by Flying grenade:

  Ultima, can help me check my answers and teacher's answer at the left column? For the 2nd product, i thought its methanoic acid, but my cher say it's co2, idk why

  
  Because methanoic acid is further oxidized to carbonic acid, which decomposes into carbon dioxide and water.
• Flying grenade

  27 May 16, 17:43

  THANKSSSSSSS ULTIMAA!!!

• Flying grenade

  28 May 16, 15:07

  Hi ultima, can help page 10 chan kim seng planning book?

  Don't understand double titration method to find the actual amount of diprotic K2CO3

• UltimaOnline

  28 May 16, 15:16

  Originally posted by Flying grenade:

  Hi ultima, can help page 10 chan kim seng planning book?

  Don't understand double titration method to find the actual amount of diprotic K2CO3

  
  This one you need actually to *DO* (not just read or type out notes for) this type of double-titration calculation question, preferably with the face-to-face guidance of your school teacher or private tutor. Cannot settle on forum.
• Flying grenade

  2 Jun 16, 12:04

  Can sodium beryllium hydride exist? NaBeH

• UltimaOnline

  2 Jun 16, 12:35

  Originally posted by Flying grenade:

  Can sodium beryllium hydride exist? NaBeH

  
  Nah beh?!? Eh your formula wrong lah!
• Flying grenade

  2 Jun 16, 13:50

  Yeah it was meant to be a joke

• UltimaOnline

  2 Jun 16, 15:34

  Originally posted by Flying grenade:

  Yeah it was meant to be a joke

  
  
• Flying grenade

  2 Jun 16, 16:07

  Originally posted by UltimaOnline:

  
  Nah beh?!? Eh your formula wrong lah!

  EHHH What's the correct formula ?????

• Flying grenade

  2 Jun 16, 16:10

  Now after attempting to check oxidation state of elements

   

  E.g. LiAlH4 

  O.S. : Li=+1 , Al=+3 , H- = -1 , hence overall ionic charge of molecule =0

  O.S. : Na=+1 , Be= +2 , H- = -1

  Hence NaBeH doesn't exist?

  Maybe NaBeH3 exists? 

• Flying grenade

  2 Jun 16, 16:12

  Or Na2BeH4

• UltimaOnline

  2 Jun 16, 16:28

  Originally posted by Flying grenade:

  Or Na2BeH4

  
  Correct. Because Be wants to have a stable octet.
• Flying grenade

  2 Jun 16, 17:41

  Originally posted by UltimaOnline:

  
  Correct. Because Be wants to have a stable octet.

   

  I dun get it ! I tot Be has to lose 2 e- to gain a stable duplet structure?

   

  If stable octet it has to gain 6 e- ! How is it possible here?

   

  Then does NaBeH3 exist?

   

  Thanksss ultima!!!

• UltimaOnline

  2 Jun 16, 18:31

  Originally posted by Flying grenade:

   

  I dun get it ! I tot Be has to lose 2 e- to gain a stable duplet structure?

   

  If stable octet it has to gain 6 e- ! How is it possible here?

   

  Then does NaBeH3 exist?

   

  Thanksss ultima!!!

  
  To understand, you must draw out the mechanism and structures of the reactants and products.

  Can exist, but won't be stable, coz Be will lack a stable octet and still kena a uninegative formal charge. Either BeH2 (lack stable octet, but at least no formal charge), or Na2BeH4 (has stable octet, but kena dinegative formal charge) are both more stable than your NaBeH3, which kena the worst of both worlds (in terms of stabilities).

  But of course, you still won't fully understand, you still have many questions, but that's enough for the forum, go ask your school teacher or private tutor.