CBSE Class 7 Answered

An acid is a compound usually having a sour taste and capable of neutralizing alkalis. It changes the colour of blue litmus paper too red. Acids contain hydrogen that can be replaced by a metal or an electropositive group to form a salt. Or They contain an atom that can accept a pair of electrons from a base. Acids are proton donors that yield hydronium ions in water solution, or electron pair acceptors that combine with electron pair donors or bases. Acids in solution have a pH below 7.0.