What is the chemical formula of gypsum?

Which substance is added to the soil to neutralize acidic soil?

What are strong and weak acids? In the following list of acids,separate strong acids from weak acids: Hydrochloric acid,citric acid,acetic acid,nitric acid,formic acid,sulphuric acid.

Which of the following are present in a dilute aqueous solution of hydrochloric acid?

In a basic aqueous solution,if the concentration of $[OH^-]$ decreases,what happens to the $pH$?

What is the $pH$ value for a neutral aqueous solution?