Which reaction represents the process of neutralization?

1) mg + 2hcl > mgcl2 + h2
2) hcl + koh > kcl + h2o
3) pb(no3)2 + cacl2 > ca(no3)2 + pbcl2
4) 2kclo3 > 2kcl + 3o2

2)

Explanation:  When an acid reacts with the base then it undergoes neutralization to form a salt and water.

1) : is an example of single replacement reaction as Mg replaces hydrogen from its salt solution.

2) : is an example of neutralization where acid and base reacts to give salt and water.

3) :  is an example of double displacement reaction in which exchange of ions take place.

4) : is an example of decomposition where a single reactant decomposes to give two or more products.