Question

Какая часть речи "за то"?

Answer 1

Зато - союз
За то - предлог с местоимением 

не путайте

Answer 2

Part of Speech of "за то"

The phrase "за то" in Russian can function as a preposition or a conjunction, depending on its usage in a sentence.

As a Preposition: When "за то" is used to indicate the purpose or reason for something, it functions as a preposition. For example, in the sentence "Я пошел в магазин за то, чтобы купить продукты" (I went to the store to buy groceries), "за то" is used as a preposition to express the purpose of going to the store.

As a Conjunction: In some cases, "за то" can also function as a conjunction, connecting two clauses or sentences. For instance, in the sentence "Он уехал, за то что был устал" (He left because he was tired), "за то" serves as a conjunction linking the reason for his departure to the action itself.

These different functions of "за то" demonstrate its versatility in the Russian language, allowing it to convey both purpose and causation in different contexts.