A small amount of a green solid is added to hydrogen peroxide solution. Bubbles are given off quickly. At the end of the reaction the green solid is still in the flask. What is the best conclusion?
The green solid is a catalyst for the decomposition
The green solid is a reactant in the decomposition
The green solid is a product of the decomposition
The green solid has no effect on the decomposition
91 exam-style questions on AQA GCSE Chemistry 1.3 Properties of transition metals, covering 1.3.1 Comparison with Group 1 elements and 1.3.2 Typical properties of transition metals. Each one has a worked solution and a mark scheme showing where the marks go.