Calculate the strength of $5$ volume ${\mathrm{H}}_2{\mathrm{O}}_2$ solution.

Melting point, enthalpy of vaporisation and viscosity data of ${\mathrm{H}}_2\mathrm{O}$ and ${\mathrm{D}}_2\mathrm{O}$ is given below:

On the basis of this data explain in which of these liquids intermolecular forces are stronger?

Rohan heard that instructions were given to the laboratory attendant to store a particular chemical i.e., keep it in the darkroom, add some urea in it, and keep it away from dust. This chemical acts as an oxidising as well as a reducing agent in both acidic and alkaline media. This chemical is important for use in the pollution control treatment of domestic and industrial effluents. Write the name of this compound.

Rohan heard that instructions were given to the laboratory attendant to store a particular chemical i.e., keep it in the darkroom, add some urea in it, and keep it away from dust. This chemical acts as an oxidising as well as a reducing agent in both acidic and alkaline media. This chemical is important for use in the pollution control treatment of domestic and industrial effluents. Explain why such precautions are taken for storing this chemical.