Study the following chemical reactions and answer the questions given below: NaOH + HNO3 NaNO3 + H2O Ca(OH)2 + 2HCl CaCl2 + 2H2O i) Write down the name of an acid and a base/alkali from the above…

Model Answer

i) Name of an acid and a base/alkali from the given reactions

From the given chemical reactions:

• Acid: Nitric acid ($\mathrm{HNO}{}_3$) and hydrochloric acid ($\mathrm{HCl}$) are acids.
• Base/Alkali: Sodium hydroxide ($\mathrm{NaOH}$) and calcium hydroxide ($\mathrm{Ca}(\mathrm{OH}){}_2$) are bases (alkalis).

NaOH+HNO₃NaNO₃+H₂O

ii) Why is it suggested to use soap to a person suffering from bee or ant bite?

When a bee or ant stings, it injects formic acid (in ants) or methanoic acid (in bees) into the skin. These acids cause pain and irritation.

HCOOH+NaOHHCOONa+H₂O

formic acidformic acidmethanoic acidmethanoic acid

Soap is basic in nature (usually alkaline due to sodium hydroxide in its preparation). When soap is applied to the affected area, it neutralizes the acidic sting through a neutralization reaction, reducing pain and irritation. For example: $$\mathrm{Formic}\mathrm{acid}(\mathrm{HCOOH})+\mathrm{NaOH}(\mathrm{from}\mathrm{soap})\to \mathrm{Sodium}\mathrm{formate}(\mathrm{HCOONa})+\mathrm{H}{}_2\mathrm{O}$$ This reaction helps in relieving the sting’s effect and provides temporary relief.

iii) 'All the bases are not alkalies.' Justify it.

The statement is true because bases and alkalies are not the same, though all alkalies are bases.

ammoniaammonia

Conclusion: While all alkalies are bases, not all bases are alkalies because alkalies must be soluble in water and produce $\mathrm{OH}{}^{-}$ ions. For example, ammonia ($\mathrm{NH}{}_3$) is a base but not an alkali because it does not release $\mathrm{OH}{}^{-}$ ions in water. Instead, it forms ammonium hydroxide ($\mathrm{NH}{}_4\mathrm{OH}$) in solution, which partially dissociates into $\mathrm{NH}{}_4{}^{+}$ and $\mathrm{OH}{}^{-}$. However, it is still considered a weak base, not a strong alkali.