8. Extraction of metal from the ore cassiterite involves\\
(A) carbon reduction of an oxide ore\\
(B) self-reduction of a sulphide ore\\
(C) removal of copper impurity\\
(D) removal of iron impurity

\section*{ANSWER: AD}
\begin{enumerate}
  \setcounter{enumi}{8}
  \item The correct statement(s) pertaining to the adsorption of a gas on a solid surface is (are)\\
(A) Adsorption is always exothermic.\\
(B) Physisorption may transform into chemisorption at high temperature.\\
(C) Physisorption increases with increasing temperature but chemisorption decreases with increasing temperature.\\
(D) Chemisorption is more exothermic than physisorption, however it is very slow due to higher energy of activation.
\end{enumerate}

\section*{ANSWER: ABD}
\begin{enumerate}
  \setcounter{enumi}{9}
  \item According to kinetic theory of gases\\
(A) collisions are always elastic.\\
(B) heavier molecules transfer more momentum to the wall of the container.\\
(C) only a small number of molecules have very high velocity.\\
(D) between collisions, the molecules move in straight lines with constant velocities.
\end{enumerate}

\section*{ANSWER: ACD}
\begin{enumerate}
  \setcounter{enumi}{10}
  \item Amongst the given options, the compound(s) in which all the atoms are in one plane in all the possible conformations (if any), is (are)
\end{enumerate}

(A)\\
\includegraphics[alt={}]{smile-4a42b1fc57068acf3d457ffe392f92472921b52b}

(B)\\
\includegraphics[alt={}]{smile-3fac329f96855d5b57c7392f0b743e7bcdaaf372}\\
(C) $\mathrm { H } _ { 2 } \mathrm { C } = \mathrm { C } = \mathrm { O }$\\
(D) $\mathrm { H } _ { 2 } \mathrm { C } = \mathrm { C } = \mathrm { CH } _ { 2 }$

ANSWER: BC

\section*{SECTION - III (Total Marks : 15)}
\section*{(Paragraph Type)}
This section contains 2 paragraphs. Based upon one of the paragraphs 3 multiple choice questions and based on the other paragraph 2 multiple choice questions have to be answered. Each of these questions has four choices (A), (B), (C) and (D) out of which ONLY ONE is correct.

\section*{Paragraph for Question Nos. 12 to 14}
When a metal rod $\mathbf { M }$ is dipped into an aqueous colourless concentrated solution of compound $\mathbf { N }$, the solution turns light blue. Addition of aqueous NaCl to the blue solution gives a white precipitate $\mathbf { O }$. Addition of aqueous $\mathrm { NH } _ { 3 }$ dissolves $\mathbf { O }$ and gives an intense blue solution.\\