The concentration of fluoride,lead,nitrate and iron in a water sample from an underground lake was found to be $1000 \ ppb, 40 \ ppb, 100 \ ppm$ and $0.2 \ ppm,$ respectively. This water is unsuitable for drinking due to high concentration of:

Match List-$I$ with List-$II$.

List-$I$	List-$II$
$A$. Sulphate	$I$. Pesticide
$B$. Fluoride	$II$. Bending of bones
$C$. Nicotine	$III$. Laxative effect
$D$. Sodium arsinite	$IV$. Herbicide

Choose the correct answer from the options given below.

$A$ biosphere is composed of

From the following,identify the reactions which are responsible for the depletion of the ozone layer.
$I. Cl\dot{O}_{(g)} + NO_{2_{(g)}} \rightarrow ClONO_{2_{(g)}}$
$II. CF_2Cl_{2_{(g)}} \xrightarrow{uv} \dot{Cl}_{(g)} + \dot{CF}_2Cl_{(g)}$
$III. \dot{Cl}_{(g)} + CH_{4_{(g)}} \rightarrow HCl_{(g)} + \dot{C}H_{3_{(g)}}$
$IV. \dot{Cl}_{(g)} + O_{3_{(g)}} \rightarrow Cl\dot{O}_{(g)} + O_{2_{(g)}}$
$V. Cl\dot{O}_{(g)} + O_{(g)} \rightarrow \dot{Cl}_{(g)} + O_{2_{(g)}}$

Among the following compounds,which one is not responsible for the depletion of ozone layer?

Which of the following molecules is present in photochemical smog?