Why is chloroform stored in dark-colored bottles?

When $3-$methylbutan$-2-$ol is treated with $HBr$,the following reaction takes place:
$CH_3-CH(CH_3)-CH(OH)-CH_3 \xrightarrow{HBr} CH_3-C(Br)(CH_3)-CH_2-CH_3$
Give a mechanism for this reaction.
(Hint : The secondary carbocation formed in step $II$ rearranges to a more stable tertiary carbocation by a hydride ion shift from $3^{rd}$ carbon atom.)

Which is the correct reactivity order for $E_2$ reaction with alcoholic $KOH$?

Chloroethane with silver acetate forms $X$ and with $LiAlH_4$ forms $Y$. What are $X$ and $Y$?

State the general reactions of alkyl halides $(RX)$ with different nucleophiles.

Which of the following compounds is not a suitable solvent for a Grignard reaction?