Much vs. A Lot

is mostly used in negative and interrogative sentences in informal situations. Whenever we use much in an affirmative sentence it sounds a little formal to the audience.

is used in negative, interrogative and affirmative sentences. In affirmative sentences, it is used as an alternative for 'much'. Although we can use 'a lot' in negative sentences and questions, it is common to use 'much' and 'many'. 'A lot' and 'a lot of' are commonly used in affirmative sentences.

is followed by singular uncountable nouns. As a result, it is followed by singular verbs as well.

is followed by both singular uncountable and plural countable nouns. So, it is obvious that we can use a lot or a lot of with either singular or plural verb.

Determiners are used before the nouns to define them. As a determiner, 'much' is used before uncountable singular nouns. As a pronoun, much is used alone with no nouns following it. As you know, adverbs can come before adjectives and other adverbs, so, 'much' as a determiner is used before adverbs and adjectives. As you can see 'a lot' is formed by two words, one is the 'article' a and one is the 'noun' lot. But as a phrase, they are used as determiners before plural countable and singular uncountable nouns , in this case, 'a lot' is followed by the term 'of'.

refer to a large amount. By quantity, we mean an amount or a number. So, these two words are being considered 'quantifiers'.