mechanism(AL5)

今日化覺友想講o下AL嘅org chem。Org chem 係今個syllabus大改咗，改以mechanism為主，每個functional group都要學一個mechanism 。其中有d都係同上一個syllabus相同，例如

1. alkane嘅free radical substitution

2. alkene嘅electrophilic addition

3. haloalkane嘅necleophilic substitution (SN1 and SN2)

4. carbonyl compound嘅nucleophilic addition

新加嘅就有

1. benzene嘅electrophilic substitution

2. carboxylic acid and its derivatives嘅nucleophilic acyl substitution。

其實e兩個mechanisms係前兩代嘅syllabus已經有o架啦。只不過係舊瓶新酒o者。

每一年AL exam都要同學仔寫其中一、兩個mechanisms，當然今年新加o個兩個就最大機會啦。所以化學友想講下e兩個mechanisms。首先，講嘅係benzene嘅electrophilic substitution，課程指定嘅example係mono-halogenation of benzene。 以下就係mono-chlorination of benzene嘅mechanism，同學仔一定一定要記熟呀:


下面係化學友做嘅simple animation，睇o下對你有冇用丫(按下先睇到):




教統局都有做咗幾個mechanisms嘅animations幫同學仔學習，可以去e個網址睇吓，做得幾好o架:
http://cd1.emb.hkedcity.net/cd/science/chemistry/s67chem/reaction_mechanism_animation_e.swf

最後就係俾條題目大家唸吓，考吓自己識唔識啦!
Methoxybenzene when treated with a mixture of concentrated HNO3 and H2SO4 gives 4-methoxy-1-nitrobenzene as one of the products. Outline a reasonable mechanism for this reaction.”