Chemical Properties of Metals Questions in English

(C) The process of adsorption of $H_2$ gas on the surface of transition metals like $Pd$,$Pt$,or $Ni$ is known as occlusion.
$H_2$ gas can be adsorbed on these metals and can be released later when required,for example,in hydrogenation reactions.
Therefore,$H_2$ (dihydrogen) is the correct answer.

(C) Vulcanization is a chemical process used to improve the physical properties of natural rubber.
In this process,natural rubber is heated with $S$ (sulfur) at a temperature range of $140^{\circ}C$ to $160^{\circ}C$.
The addition of sulfur creates cross-links between the polymer chains of rubber,which makes the rubber harder,more durable,and resistant to heat and wear.
Therefore,the correct non-metal used is sulfur.

(C) When metals react with dilute sulfuric acid $(H_2SO_4)$,they displace hydrogen gas and form their respective metal sulphates.
The general chemical equation is: $Metal + Dilute \ H_2SO_4 \rightarrow Metal \ Sulphate + Hydrogen \ gas$.
For example,when Zinc $(Zn)$ reacts with dilute sulfuric acid,it forms Zinc Sulphate $(ZnSO_4)$ and releases Hydrogen gas $(H_2)$.

(B) Vulcanization is a chemical process for converting natural rubber or related polymers into more durable materials by the addition of sulfur or other equivalent curatives.
$ZnO$ (Zinc Oxide) is commonly used as an activator or catalyst in the vulcanization process to increase the rate of reaction and improve the physical properties of the rubber.