Question

Refraction from denser to rarer medium formula derivation

Answer 1

When light travels from a denser medium to a rarer medium, it bends away from the normal, as illustrated to the left. This behavior follows from Snell's Law. As you saw before, the larger angle must be in the medium having the lower index of refraction. Due to this change in speed light bends and travels when passing from one medium to other medium. When the light ray passes from rarer medium to denser medium it bends towards the normal. ... Example: Light ray passing from Glass to Air (Air - rarer medium, Glass - denser medium.) Related Terms: Reflection.

Answer 2

Explanation:

HBr   +   (CH2CO)2NBr   →   Br2   +   (CH2CO)2NH

This mechanism is essentially the same as that for the free radical halogenation of alkanes, with NBS serving as a source of very low concentrations of bromine. Unsymmetrical allylic radicals will react to give two regioisomers. Thus, 1-octene on bromination with NBS yields a mixture of 3-bromo-1-octene (ca. 18%) and 1-bromo-2-octene (82%) - both cis and trans isomers.

RCH2CH=CH2   +   (CH2CO)2NBr  →   RCHBrCH=CH2  +   RCH=CHCH2Br   +   (CH2CO)2N