No, Matter cannot be created nor deastroyed.
The focal length, like you said it's the distance between the FOCAL point and the mirror.
Hope this helps.... :)
<span><span>The reaction is as follows:
C6H6 </span>+ HNO3 + H2SO4 ------------> </span>C6H5NO2<span> + H</span>2<span>O
(BENZENE) (NITRIC ACID)(CATALYST)
</span>NO2(+) is the electrophile that acctacks on the benzene ring in nitration process.
