How many of the following responses are true? 1. When dissolved in water, the th

Question

How many of the following responses are true?

1. When dissolved in water, the third dissociation of H3PO4 will not produce a significant amount of the H+ ion

2. Successive Ka values for polyprotic acids become larger, and are therefore more important in determining the pH of a solution

3. The % dissociation of H3PO4 is greater than that of a strong acid because there are more moles of protons in the polyprotic acid

4. HCN is a strong acid and will dissociate completely in water

5. HI is a strong acid and will dissociate completely in water

obviously, i know that 4 is false and 5 is true but i dont know about 1,2,3.

Explanation / Answer

Answer – We are given, the statements and need to find out the true statements.

1)True - When dissolved in water, the third dissociation of H3PO4 will not produce a significant amount of the H+ ion, since the third ionization constant for H3PO4 is too small and it is not affect much more on the H+, so this statement is true.

2) False -Successive Ka values for polyprotic acids become smaller than larger, and are therefore more important in determining the pH of a solution.

3) False- Since the % dissociation of H3PO4 is depends on the dissociated moles by initial moles and strong acid % dissociation of H3PO4 or strong acid are same at same initial concentration.

4) False- HCN is weak acid, so it is not dissociating completely in water.

5) Ture- HI is strong acid, since it dissociated completely.

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