Magnesium ribbon is rubbed before burning because it has a coating of

Oxidation is a process which involves

Give the ratio in which hydrogen and oxygen are present in water by volume.

\(
\begin{aligned}
&\mathrm{MnO}_{2}+4 \mathrm{HCl} \rightarrow 2+2 \mathrm{H}_{2} \mathrm{O}+\mathrm{Cl}_{2}\\
&\text { Identify the substance oxidized in the above equation. }
\end{aligned}
\)

Which of the following is an endothermic process?

What type of chemical reactions take place when electricity is passed through water?

A substance added to food containing fats and oils is called

\(
\begin{aligned}
\mathrm{Pb} + \mathrm{CuCl}_{2} &\rightarrow \mathrm{PbCl}_{2} + \mathrm{Cu}
\end{aligned}
\)

The condition produced by aerial oxidation of fats and oils in foods marked by unpleasant smell and taste is called:

Which of the following gases can be used for storage