Question

How can I balance this chemical equation? Potassium metal and chlorine gas combine to form potassium chloride.

Answer 1

Hint: First, write the chemical equation in which there are the given two reactants i.e., potassium and chlorine, which will combine to form one product i.e., potassium chloride. The formula for potassium chloride is $KCl$.

Complete step by step answer:
In the statement in the question, there are two reactants and one product. The reactants are potassium and chlorine, and the product is potassium chloride.
The potassium is the element of group 1 in the s-block whose symbol is K and its valency is 1.
The chlorine is the element of group 17 in the p-block whose symbol is $Cl$and it is always written in elemental form having two atoms having formula $C{{l}_{2}}$.
Potassium chloride is a compound having two elements i.e., potassium and chloride, and its formula is $KCl$.
So, the reaction will be:
$K+C{{l}_{2}}\to KCl$
Now, the potassium is the metal so, we have to write (s) with potassium, chlorine is in the gaseous state so, we have to write (g) with chlorine, and potassium chloride is solid so, we have to write (s) with potassium chloride.
$K_{(s)}+C{{l}_{2}}_{(g)}\to KCl_{(s)}$
Now, for balancing the equation, there are two chlorine atoms at the reactant side and there is only one chlorine atom at the product side. So, we have to multiply 2 with $KCl$ and then we have to multiply the potassium metal with 2.
The balanced equation will be:
$2K_{(s)}+C{{l}_{2}}_{(g)} \to 2KCl_{(s)}$

Note: Since, this reaction doesn't have hydrogen and oxygen atoms, but if the equation has hydrogen and oxygen atoms, then we to first balance all the elements other than O and H, and after balancing hydrogen, check all the other atoms are balanced then only proceed for the balancing of the oxygen atoms.