The order of reactivity of the following compounds towards dilute aqueous $KOH$ in $SN_1$ reaction is
$I$. $CH_3CH_2CH_2CH_2Br$
$II$. $CH_3CH_2CHBrCH_3$
$III$. $(CH_3)_2CHCH_2Br$
$IV$. $(CH_3)_3CBr$

In the given reaction
$CH_3-CH(OTs)-CH_2-CH_2-CH(OTs)-CH_3$ $\xrightarrow[(ii) \ KOH]{(i) \ SH^{\ominus} (one \ equivalent)}$ $[X]$
$[X]$ will be :

Compare the rate of reaction with $AgNO_3$ for the following compounds:

The reaction of ethyl bromide with lead-sodium alloy gives ......... .

Two bottles containing $C_6H_5I$ and $C_6H_5CH_2I$ have lost their original labels. They are labeled as $A$ and $B$ for testing. $A$ and $B$ are taken separately in test tubes and boiled with $NaOH$ solution. The final solution of each test tube is acidified with dilute $HNO_3$ and a little $AgNO_3$ is added. Solution $B$ gives a yellow precipitate. Which of the following statements is correct?

Write a note on Grignard Reagent.