Question

Potassium reacts with water to produce _____ flame.

Answer 1

Hint: As we know that potassium is an alkali metal and very reactive in nature. When it is added to water, the potassium metal floats and melts as well as sets on fire. This metal moves around quickly on the water and spreads the fire everywhere. So here we have to tell what type of flame gets produced when potassium reacts with water.

Complete answer:
Let us first understand about potassium metal and its nature followed by the type of fame get produced when it reacts with water as follows:-
Potassium: It is a chemical element denoted by the symbol ‘K’ and has atomic number 19. It is a silvery-white metal which is so soft enough to be cut with a knife just by a little force. In the periodic table, potassium belongs to the alkali metals group, all of them have a single valence electron in the outermost shell which can be easily removed to create an ion with a positive charge (a cation). It can combine with anions to form ionic salts and potassium generally occurs only in form ionic compounds in nature.
-As potassium is highly reactive, so when it reacts with water following reaction takes place:-
$2K(s)+2{{H}_{2}}O(l)\to 2KOH(aq)+{{H}_{2}}(g)$
Here we can see that when potassium reacts with water, it produces potassium hydroxide along with hydrogen gas. This reaction is so vigorous and exothermic that hydrogen gas liberated during the reaction catches fire spontaneously. The flame produced is a lilac-colored flame. Sometimes we can also see explosions at the end of the reaction.
-Conclusion from the above data is that potassium reacts with water to produce lilac-colored flame.

Note:
-This reaction is so fast and exothermic that it can even take place in cold water as well.
-Same nature is also shown by another alkali metal that is sodium (Na). It also vigorously reacts with water and catches fire.