$Cl_2 + \mathop{NaOH}\limits_{(\text{dil and cold})} \longrightarrow A + B + H_2O$. The anions of $A$ and $B$ are respectively . . . . . . .

An iron rod is placed parallel to a magnetic field of intensity $2000 \ A \ m^{-1}$. The magnetic flux through the rod is $6 \times 10^{-4} \ Wb$ and its cross-sectional area is $3 \ cm^2$. The magnetic permeability of the rod in $Wb \ A^{-1} \ m^{-1}$ is:

The angle between the tangents drawn from the point $(1,4)$ to the parabola $y^2=4x$ is

Solvay process is used in the manufacture of

$6.023 \times 10^{22}$ molecules are present in $10 \ g$ of a substance $x$. The molarity of a solution containing $5 \ g$ of substance $x$ in $2 \ L$ of solution is $\dots \dots \dots \times 10^{-3} \ M$.

What is preserved in a museum?