Question

Fill in the blanks with the appropriate words.

An acid is a compound which when dissolved in water forms the (a)_______ ions as the only (b)__________ ions. (c) A base is a compound which if _______ in water contains (d)_______ ions. A base reacts with an acid to form a (e) _______ and water only. This type of reaction is known as (f) ________.

Answer 1

(a) Hydronium ions $\left({\mathrm{H}}_3{\mathrm{O}}^{+}\right)$

1. All acids compulsorily have hydrogen as their constituent in the form of proton $\left({\mathrm{H}}^{+}\right)$.
2. When dissolved in water, one water molecule $\left({\mathrm{H}}_2\mathrm{O}\right)$ gains a hydrogen proton $\left({\mathrm{H}}^{+}\right)$, finally forming hydronium ions $\left({\mathrm{H}}_3{\mathrm{O}}^{+}\right)$.

(b) positively charged ions

1. The hydrogen atom, after losing its only electron gains a positive charge and is therefore referred to as hydrogen proton $\left({\mathrm{H}}^{+}\right)$.
2. Hydronium ions $\left({\mathrm{H}}_3{\mathrm{O}}^{+}\right)$ is a combination of the water molecule $\left({\mathrm{H}}_2\mathrm{O}\right)$ and hydrogen proton $\left({\mathrm{H}}^{+}\right)$, therefore it has a positive charge, due to the hydrogen proton.
3. The other elements combined with hydrogen in the acids have a negative charge, as they are generally non-metals, which accept electrons from other elements, or metals in general.
4. So, the hydronium ions $\left({\mathrm{H}}_3{\mathrm{O}}^{+}\right)$ are the only positively charged ions formed.

(c) dissolved

1. A base which can be dissolved in water is called an alkali.
2. All bases are not soluble in water.
3. All alkalis are bases, but all bases are not alkalis.

(d) hydroxide ions $\left({\mathrm{OH}}^{-}\right)$

1. A base usually is a metallic oxide or hydroxide.
2. Alkalis are generally metallic hydroxides.
3. Metals are electron donors or positively charged ions, which means to form a compound, hydroxide ions need to be negatively charged.
4. The negatively charged hydroxide ions are released in water to combine with the positively charged hydrogen ions.

(e) salt

1. When an acid reacts with a base, the products formed are salt and water only.
2. It is because acids are non-metals combined with hydrogen ions and bases are metals combined with oxide or hydroxide ions.
3. The metals from the bases and non-metals from the acids combine to form the salt.
4. The hydrogen ions and the hydroxide or oxide ions combine to form water.

(f) neutralization reaction

1. When an acid reacts with a base to form salt and water as the only products, the reaction taking place is called a neutralization reaction.

Therefore, an acid is a compound that when dissolved in water forms the (a) hydronium ions $\left({\mathrm{H}}_3{\mathrm{O}}^{+}\right)$ ions as the only (b) positively charged ions. (c) A base is a compound which if dissolved in water contains (d) hydroxide ions $\left({\mathrm{OH}}^{-}\right)$ ions. A base reacts with an acid to form a (e) salt and water only. This type of reaction is known as (f) neutralization reaction.