Halide Ions

Question 0

To reduce something, the halide ion needs to……

Answer 0

Lose an electron from its outer shell. How easy this is depends on the attraction between the nucleus and the outer electrons

Question 1

The reducing power of halides ………… down the group. Why?

Answer 1

Increases

The ions get bigger so the electrons are further away from the positive nucleus.

There are extra inner electron shells, so greater shielding

Question 2

What do halides react with

Answer 2

Conc Sulphuric acid To give a hydrogen halide

Question 3

Silver nitrate solution is used to test for ……

Answer 3

Halides

First add dilute nitric acid to remove ions which might interfere with the test. Then add silver nitrate solution. A precipitate is formed (of the silver halide). The colour of the precipitate identifies the halide. To be extra sure, you can test your results by adding ammonia solution. Each silver halide has a different solubility in ammonia

Question 4

Why is acidified silver nitrate used to test for halide ions

Answer 4

Because it forms an insoluble salt which is also coloured which means the colour can identify the halide