Lesson 4: Metal Hydroxide Precipitates

Question 1

Solutions of WHICH? 3 metal ions produce a white precipitate.

Answer 1

• Aluminium
• Calcium
• Magnesium

Question 2

What happens when you add excess sodium hydroxide solution to a solution containing aluminium ions?

Answer 2

• The aluminium hydroxide precipitate dissolves in the excess sodium hydroxide solution.

Question 3

What is the negative ion in all of the precipitates formed when you react the metal ion solution with sodium hydroxide solution?

Answer 3

• The hydroxide ion.

(other than halide precipitates CONTAIN silver and halide ion.)

Question 4

What colour precipitate does copper (II) form when added to sodium hydroxide solution?

Answer 4

• ## Copper (II) forms a blue precipitate.

Question 5

What colour precipitate does iron (II) form when added to sodium hydroxide solution?

Answer 5

• Iron (II) forms a green precipitate.

Question 6

What colour precipitate does iron (III) form when added to sodium hydroxide solution?

Answer 6

• Iron (III) forms a brown precipitate.

Question 7

Which common ion is usually bonded to ions that we are testing for by using sodium hydroxide?

Answer 7

• Nitrate ions
• (ie. compound = iron nitrate.)