HELP ~chem要攞A ge入黎答=3333333333333333333=

samson2020

HKCEE 1996 Q21



21. Which of thefollowing statements concerning chlorine isINCORRECT?
A. It can kill germs.
B. It can turn bromine water colorless.
C. It can oxidize iodide ions to iodine molecules.
D. It can be produced by the reaction between dilute sulphuric acid and sodium hypochlorite solution.



ans is B



but i wonder how D work????

piyopiyo

H+  + OCl- + Cl - --> Cl2 + H2O

samson2020

原帖由 piyopiyo 於 10-4-2008 20:58 發表
H+  + OCl- + Cl - --> Cl2 + H2O

where is the Cl- from- -??? only NaClO given

piyopiyo

原帖由 samson2020 於 10-4-2008 20:59 發表

where is the Cl- from- -??? only NaClO given

oops,made a mistake,,,then it should be

4H+ + 2OCl-  --> 2Cl2 + 2H2O...

samson2020

原帖由 piyopiyo 於 10-4-2008 21:01 發表

oops,made a mistake,,,then it should be

4H+ + 2OCl-  --> 2Cl2 + 2H2O...

@_@你條式系邊度睇番來?

Zend

原帖由 samson2020 於 10-4-2008 13:28 發表

@_@你條式系邊度睇番來?

you can know, but not necessary...

piyopiyo

原帖由 samson2020 於 10-4-2008 21:28 發表

@_@你條式系邊度睇番來?

錯的[[tk_02]]
OCl- 的Cl ON 是 +1 ... [[tk_02]]

4H+ + 2OCl- -->Cl2 + 2H2O ,,,charge唔balance, 突左2粒2H+出泥,要有第2d野收 e-...

應該唔會係咁掛
2H+ + 2e- --> H2...

6H+ + 2OCl2 ---> Cl2 + 2H2O + H2 [[tk_11]]

真係一味靠估,是否out c 的[[tk_19]]

[ 本帖最後由 piyopiyo 於 10-4-2008 21:47 編輯 ]

Puppet

I think B and D are both incorrect, but B is more incorrect.

jackiema

你可以話係因為 OCl- 會 decompose 做 Cl- 同 O2...
上一上維基, be right back

LULU:)

D係岩架∼會出ＣＬ２（Ｇ）
而Ｂ因為ＣＬ較溴強既氧化劑∼所以唔可以比電子溴∼溴唔可以變離子∼所以無得變無色∼