How would you prove that a given colourless liquid is an acid? AND What type of acid does gastric juice falls in?

How many miles of calcium oxide will be produced when 1.6 miles of iron (iii) oxide react with calcium phosphate

The melting point of sulfur is 115 °c and its boiling point is 445 °c. what state would sulfur be in at 200 °c?

Consider the directing effects of the substituents on salicylamide and predict the possible structures of the iodination products. which do you think will be the major product?