Why did industrialization lead to imperialism?
There are two ways in which industrialization led to imperialism. First, industrialization made imperialism more possible. Second, it made imperialism more necessary.
Industrialization helped make it possible for European countries (along with the US and, later, Japan) to engage in imperialism. When these countries industrialized, they gained the ability to created large numbers of powerful weapons. They could, for example, build massive steamships with huge guns. They could mass-produce small arms for foot soldiers to carry. Because they could make so many weapons that were so powerful, they were able to dominate other people and imperialize them.
Industrialization also made it necessary (or made the Europeans think it was necessary) to engage in imperialism. As these countries industrialized, they started to need sources of raw materials. They also started to need larger markets in which to sell all the goods they could produce. They felt that they had to have empires to fulfill both of these needs. They believed they needed empires from which they could get raw materials cheaply. They believed they needed empires whose people could be a captive market for their manufactured goods. In these ways, they felt that industrialization necessitated imperialism.
Thus, industrialization led to imperialism by making imperialism both more possible and more necessary.