Pickles and lemons have a sour taste. what types of substances are in pickles to give them this sour taste

The taste of Acid is Sour, that of Base is Bitter and salt is salty. So, Pickle and Lemons give sour taste due to presence of Acids. The sour taste of Lemon is due to presence of Citric Acid in it. While the sour taste of Pickle is due to presence of Vinegar (5% Acetic Acid Solution). Vinegar is mainly used to prevent the Pickle from Bacterial Attack.