Acids turn blue litmus indicator paper red. Universal Indicator paper changes colour to yellow, orange or red in an acidic solution. Acids will react with the following chemicals and these will neutralise the acid. Alkalis A base is a compound that reacts and neutralises an acid. The reaction forms a salt and water.
Alkalis are a type of base.
Alkalis are bases that dissolve in water. Alkalis are also compounds that react and neutralise acids. They also form a salt and water in the reaction. Alkalis turn red litmus indicator paper blue and they cause Universal Indicator paper to turn blue or purple. Alkaline solutions have a pH valve greater than 7.