A metal X available in the form of ribbon burns in air with a dazzling white light once heated to its ignition temperature. It leaves a white powder Y which dissolves in water. The solution so formed turns red litmus blue. Identify X and Y and write a balanced chemical equation of the reaction.
(a) Identify 'X' and 'Y'.
(b) Write a balanced chemical equation for this reaction.

2

(a)

List four changes which help us to determine whether a chemical reaction has taken place

2

(a)

Give one example of a combination reaction in which an element combines with a compound to give you a new compound

2

(a)

Give two examples in which reactants react to show combination reaction and a new product is formed. This new product decomposes to give the initial reactants.
\( \text { e.g., } X+Y \stackrel{\text { combination }}{\longrightarrow} Z \ \ \ \ \ Z \stackrel{\text { decomposition }}{\longrightarrow} X+Y \) 

2

(a)

Why are certain reagents like silver bromide stored in dark bottles in the labs?

2

(a)