Four reactions are shown below in the diagram:

Which reactions produce water?

1. 1 and 2
2. 1 and 3
3. 3 and 4
4. 2 and 3

When compound X reacts with dilute sulphuric acid, it releases a gas that turns acidified potassium dichromate solution from orange to green. Which of the following could be compound X?

1. Lead nitrate
2. Copper carbonate
3. Sodium chloride
4. Potassium sulphite

Identify from the following metal oxide which can react with an acid as well as an alkali.

1. Silver oxide
2. Calcium oxide
3. Copper(II) oxide
4. Aluminium oxide

The structures of four hydrocarbons are shown below:

How many isomers of butene are there?

1. 1
2. 2
3. 3
4. 4