Amphoteric Species and Polyprotic Acids

The video tutorial explains amphoteric species, focusing on their ability to act as both acids and bases. Water is highlighted as a prime example, demonstrating its dual role in chemical reactions. The video also covers polyprotic acids, which can form amphoteric species upon partial dissociation. Common traits of amphoteric species, such as possessing an H+ and a negative charge, are discussed, with water being an exception. The tutorial concludes with questions to test understanding.

What is the primary characteristic of an amphoteric species?

• It cannot act as either an acid or a base.

• It can act as both an acid and a base.

• It can only act as a base.

• It can only act as an acid.

How does water act as an acid?

• By accepting an electron.

• By donating an H+ to form OH-.

• By accepting an H+ to form H3O+.

• By donating an electron.

What is formed when water acts as a base?

• OH-

• H2O

• H2O2

• H3O+

What is the conjugate base formed when water acts as an acid?

• H+

• H2O2

• OH-

• H3O+

Which of the following is a polyprotic acid?

• HCl

• NaOH

• CH4

• H2SO4

What happens to polyprotic acids to form amphoteric species?

• They partially dissociate.

• They react with bases.

• They gain an electron.

• They lose all their H+ ions.

Which of the following is NOT a polyprotic acid?

• H2SO4

• H3PO4

• H2CO3

• HCl

Which of the following is a characteristic of amphoteric species?

• They have multiple positive charges.

• They have a positive charge.

• They have no charge.

• They have a negative charge and at least one H+.

Why is water an exception to the general rule for amphoteric species?

• It has multiple negative charges.

• It has no hydrogen.

• It has no negative charge.

• It has a positive charge.

Which of the following species can be amphoteric?

• A species with no charge.

• A species with only a positive charge.

• A species with hydrogen and a negative charge.

• A species with no hydrogen and a positive charge.