Bromine is commercially prepared from sea water by displacement reaction:
$Cl_2 + 2Br^{-}_{(aq)} \to 2Cl^{-}_{(aq)} + Br_2$
$Br_2$ gas thus formed is dissolved into a solution of $Na_2CO_3$ and then pure $Br_2$ is obtained by treatment of the solution with:

Example of a biodegradable polymer pair is

$A$ given mass of a gas is compressed isothermally until its pressure is doubled. It is then allowed to expand adiabatically until its original volume is restored and its pressure is then found to be $0.75$ of its initial pressure. The ratio of the specific heats of the gas is approximately :

An eight-digit number divisible by $9$ is to be formed using digits from $0$ to $9$ without repeating the digits. The number of ways in which this can be done is: (in $(7!)$)

Two conducting circular loops of radii $R_1$ and $R_2$ are placed in the same plane with their centres coinciding. If $R_1 >> R_2$,the mutual inductance $M$ between them will be directly proportional to

If the normal to the parabola $y^2=4x$ at $P(1,2)$ meets the parabola again at $Q$,then the coordinates of $Q$ are