i) Why is sodium kept immersed in kerosene oil?
ii) Which gas is produced when dilute hydrochloric acid is added to a reactive metal?
VerifiedHint: Sodium is an alkali metal and present in the first group of the periodic table. Its atomic number is 11. It can easily donate one electron to achieve a stable electronic configuration.
HCl is a strong acid and reacts with metals but generally does not react with non - metals.
Complete answer:
i) Sodium $(N{a})$ is a very reactive metal and when it comes into the contact of oxygen \[({O_2})\], carbon dioxide $(C{O_2})$ and moisture $({H_2}O)$, present in the atmosphere or air, it gets vigorous and catches fire.
Interestingly, sodium metal is found to be non-reactive in kerosene oil. Therefore, the sodium metal is kept immersed in the kerosene oil to avoid the probabilities of accidental fire and minimize the chances of severe injuries or damages.
ii) When a reactive metal $(M)$ is treated with dilute hydrochloric acid $(HCl)$, displacement reaction takes place leading to the formation of a salt i.e. metal chloride $(MCl)$ and liberation of hydrogen $({H_2})$ gas.
The reaction can be illustrated as follows: $M + HCl(aq.) \to MCl + {H_2} \uparrow $
Note:
The reactive metals are the type of metals which could form reactions with acids, water or moisture, mineral acids and other potent acids. Reactive Metals like sodium, potassium, and lithium are highly flammable in nature. These reactive metals when in contact with air (presence of oxygen or moisture) catches fire and thus they are kept immersed in the kerosene oil to avoid injuries due to the accidental fire. The sodium metal is even not kept immersed in water because it reacts vigorously in the aqueous medium and forms sodium hydroxide with the liberation of hydrogen gas. The liberation of hydrogen gas (flammable), again can lead to accidental injuries due to severe ignitions.
