Taste sour, feel like water (for for broken or injured skin it stings), react vigorously with many metals such as Mg, Zn, Fe, and Al, conduct electricity well (are electrolytes), and turn litmus paper from blue to red.
Taste bitter, feel slippery and smooth, Do not react with most metals, conduct electricity well (are electrolytes), and turn litmus paper from red to blue.
Temperature, concentration, and pressure (for gases).
When you raise the temperature of a reaction, there is more kinetic energy, and thus more collisions, speeding up the reaction. Higher concentration means more molecules, more collisions, and so faster reaction. When you increase the pressure for gases, the molecules are more compacted, so there are more collisions, and thus faster reaction rate again.