Solubility of Phosphates in Water

The video tutorial explores the solubility of aluminum phosphate (AlPO4) in water. It begins by introducing the concept of solubility and the specific case of aluminum phosphate. The instructor refers to solubility rules, noting that most phosphates are insoluble in water, with exceptions for group 1 elements and ammonium phosphate. Aluminum phosphate is confirmed to be insoluble. A solubility table is used to verify this conclusion, showing that AlPO4 remains mostly solid in water. The video concludes by reiterating that while a small amount may dissolve, aluminum phosphate is generally considered insoluble.

What is the general solubility rule for phosphates in water?

• Phosphates are soluble only in acidic solutions.

• Phosphates are always insoluble in water.

• Most phosphates are insoluble in water.

• All phosphates are soluble in water.

Which elements make phosphates soluble in water according to the solubility rules?

• Elements in group 2 and ammonium

• Elements in group 1 and ammonium

• Halogens

• Transition metals

What does the solubility table confirm about aluminum phosphate?

• It is highly soluble in water.

• It is slightly soluble in water.

• It is insoluble in water.

• It dissolves completely in water.

What happens to most of the aluminum phosphate when placed in water?

• It changes color.

• It remains mostly as a solid.

• It reacts with water to form a gas.

• It dissolves completely.

Why is aluminum phosphate classified as insoluble?

• Because only a small amount dissolves, leaving most as a solid.

• Because it reacts with water to form a new compound.

• Because it changes state when in contact with water.

• Because it dissolves completely in water.