The question is incomplete, here is a complete question.
Categorize each reaction into types of chemical reactions.
(1)

(2)

(3)

(4)

Answer :
(1) Precipitation reaction
(2) Neutralization reaction
(3) Double-displacement reaction
(4) Single replacement reaction
Explanation :
(1) The balanced chemical reaction is:

This reaction is a precipitation reaction in which an insoluble salt formed when two aqueous solutions are combined. The insoluble salt that settle down in the solution is known an precipitate.
(2) The balanced chemical reaction is:

This is a neutralization reaction in which an acid react with a base react to give salt and water as a product that means it reacts to give a neutral solution.
(3) The balanced chemical reaction is:

The given reaction is a double-displacement reaction in which the cation of two reactants molecule exchange their places to give two different products.
(4) The balanced chemical reaction is:

This reaction is a single replacement reaction in which the the more reactive element replace the less reactive element.