Even though acids and bases are fundamentally different in nature, there are some similarities between them.
For example, both acids and bases cause a chemical reaction when applied to litmus paper -acid changes blue litmus paper to red, while bases turn red litmus paper to blue.
Also, when present in concentrated amounts, both acids and bases have been known to have corrosive properties. Another similarity is that both acids and bases are soluble in water -meaning that they can be diluted to a weaker concentration when mixed with water.
Also, when dissolved in water, they both produce hydrogen ions -hydrogen ions in the case of acids, and hydroxyl ions in the case of bases. Both acids and bases are good conductors of electricity, as they are electrolytes. Both acids and bases produce extreme results when measured on a pH scale -acids measure less than 7, while bases measure above 7.