Q4.4 - Chemistry: Molecular Nature Of Matter And Change

Question

Question: (a) Name three common weak acids. 

(b) Name one common weak base. 

(c) What is the major difference between a weak acid and a strong acid or between a weak base and a strong base, and what experiment would you perform to observe it?

 

Step-by-Step Solution

Answer

Answer

 

(a)$HF,H_{3}P{O}_4$ and ${\mathrm{CH}}_3\mathrm{COOH}$

(b) ${\mathrm{NH}}_4\mathrm{OH}$

(c) By bulb glowing experiment we can observe and differentiate between strong and weak acid or base.

 

Step 1: Definition of acid and base

Acids are those compounds that give${\mathrm{H}}^{+}$ ions, whereas bases are those compounds that give$\mathrm{OH}$ ion in an aqueous solution.

Step 2: Write name of three common weak acids

The name of the three weak acids are:

1. Hydrofluoric Acid (HF)
2. Phosphoric Acid  ${\mathrm{CH}}_3{\mathrm{PO}}_4$
3. Acetic acid  ${\mathrm{CH}}_3\mathrm{COOH}$

Step 3: Write name of one common weak base

The name of one weak base is:

Ammonium Hydroxide $\left({\mathrm{NH}}_4\mathrm{OH}\right)$

Step 4: Experiment to differentiate between acid and base

The major difference between a weak acid and a strong acid or between a weak base and a strong base is that the strong acid or base dissociates completely in the aqueous solution while the weak acid or base does not dissociate completely.

By bulb glowing experiment we can observe and differentiate between strong and weak acid or base.

.In water, strong acids and strong bases dissociate completely into ions. Therefore, like soluble ionic compounds, they are strong electrolytes and conduct a current. So when a bulb is connected, the bulb glows brightly.

In contrast, weak acids and weak bases dissociate into ions very little, and most of their molecules remain intact. As a result, they conduct only a small current and are weak electrolytes. As a result, the brightness of the bulb decreases.