Solution:The given statement is true.
Concept- The following are the signs that let us know if the reaction has happened or not: -
Temperature change: When a reaction takes place, the mixture or solution either gets hotter or colder.
Change in colour: We can state that a reaction has taken place when a coloured solution changes colour or a colourless solution begins to take on some colour. For instance, when mixing colourless substrates to make dibenzylideneacetone, the result is a brilliant yellowish substance.
Gas emission: This refers to the release or evolution of gases or fumes that are produced during a reaction. For instance, hydrogen gas is created when salt and alcohol are combined.
Precipitate formation: If we combine two liquids and a precipitate forms at the bottom of the beaker or test tube, we have experienced a reaction. For instance, when silver nitrate and sodium chloride solution are combined, a white precipitate results.
Change in pH: A reaction occurs when two solutions with differing pH values are combined, and the resulting solution has a pH that is entirely different.
Hence, the given statement is true.