Question

How many ions are formed during the dissociation of 500 molecules of carbonic acid if it dissociates in the first degree by 20%, and in the second degree by 1%?

Answer 1

To determine the number of ions formed during the dissociation of 500 molecules of carbonic acid, we need to consider its dissociation reactions. Carbonic acid (H2CO3) can dissociate into two stages:

1. First-degree dissociation: H2CO3 ⇌ HCO3- + H+ (20% of the 500 molecules dissociate in the first degree)

2. Second-degree dissociation: HCO3- ⇌ CO32- + H+ (1% of the remaining HCO3- molecules from the first degree dissociate in the second degree)

Let's calculate step by step:

Step 1: First-degree dissociation 20% of 500 molecules = 0.20 * 500 = 100 molecules dissociate into HCO3- and H+ ions.

Step 2: Second-degree dissociation From the first-degree dissociation, we had 100 HCO3- molecules. Now, 1% of these dissociate in the second degree: 1% of 100 = 0.01 * 100 = 1 molecule dissociates into CO32- and H+ ions.

Total number of ions formed:

• H+ ions from the first-degree dissociation: 100 (from H2CO3) + 1 (from HCO3-) = 101 H+ ions
• HCO3- ions: 100 (from H2CO3)
• CO32- ions: 1 (from HCO3-)

So, during the dissociation of 500 molecules of carbonic acid, we have:

• 101 H+ ions
• 100 HCO3- ions
• 1 CO32- ion