Which one is a chemical change: Fermentation of fruit juice or diluting fruit juice?

Which mixture of two gases,taken in equal proportions in a gas jar,reacts in the presence of sunlight?

Give reason why:
$(i)$ White coloured silver chloride turns grey when kept in sunlight.

What do you mean by a precipitation reaction? Explain by giving examples.

When potassium iodide solution is added to a solution of lead $(II)$ nitrate in a test tube,a precipitate is formed.
$(i)$ Write a balanced chemical equation for this reaction.
$(ii)$ What type of reaction is this?

Which one of the following processes involves chemical reactions?