Question

Write the balanced equation for the following chemical equations:
Sodium + Water $\to$ Sodium hydroxide + Hydrogen
(A)- ${\text{2Na}}\left( {\text{s}} \right){\text{ + 2}}{{\text{H}}_{\text{2}}}{\text{O}}\left( {\text{l}} \right) \to {\text{2NaOH}}\left( {{\text{aq}}} \right){\text{ + }}{{\text{H}}_{\text{2}}}\left( {\text{g}} \right)$
(B)- ${\text{Na}}\left( {\text{s}} \right){\text{ + }}{{\text{H}}_{\text{2}}}{\text{O}}\left( {\text{l}} \right) \to {\text{NaOH}}\left( {{\text{aq}}} \right){\text{ + }}{{\text{H}}_{\text{2}}}\left( {\text{g}} \right)$
(C)- ${\text{2Na}}\left( {\text{s}} \right){\text{ + 2}}{{\text{H}}_{\text{2}}}{\text{O}}\left( {\text{l}} \right) \to {\text{NaOH}}\left( {{\text{aq}}} \right){\text{ + }}{{\text{H}}_{\text{2}}}\left( {\text{g}} \right)$
(D)- ${\text{Na}}\left( {\text{s}} \right){\text{ + }}{{\text{H}}_{\text{2}}}{\text{O}}\left( {\text{l}} \right) \to 2{\text{NaOH}}\left( {{\text{aq}}} \right){\text{ + }}{{\text{H}}_{\text{2}}}\left( {\text{g}} \right)$

Answer 1

For balancing any chemical equation we have to maintain the molecularity of each atom on both the sides of the chemical reaction i.e. on the reactant side and also on the product formation side.

Complete step by step answer:
For balancing the chemical reaction first we calculate the number of each atom on the left hand side as well as on the right hand side of the given chemical equation.
It is given that, sodium reacts with water to form sodium hydroxide & hydrogen gas i.e.
Sodium + Water $\to$Sodium hydroxide + Hydrogen
And chemical equation for this reaction is shown as follow:
${\text{Na}}\left( {\text{s}} \right){\text{ + }}{{\text{H}}_{\text{2}}}{\text{O}}\left( {\text{l}} \right) \to {\text{NaOH}}\left( {{\text{aq}}} \right){\text{ + }}{{\text{H}}_{\text{2}}}\left( {\text{g}} \right)$
Above given chemical equation is not present in the balanced form because:
-In the left hand side as well as on the right hand side only one sodium atom (${\text{Na}}$) and oxygen atom (${\text{O}}$) is present which is correct.
-But on the left hand side or on the reactant side two atoms of hydrogen (${\text{H}}$) are present and on the right hand side or on the product side three atoms of hydrogen (${\text{H}}$) are present, which is not correct.
So balanced chemical equation for the given reaction is shown as follow:
${\text{2Na}}\left( {\text{s}} \right){\text{ + 2}}{{\text{H}}_{\text{2}}}{\text{O}}\left( {\text{l}} \right) \to {\text{2NaOH}}\left( {{\text{aq}}} \right){\text{ + }}{{\text{H}}_{\text{2}}}\left( {\text{g}} \right)$
Where each atom has equal molecularity on the left hand side as well as on the right hand side of the chemical reaction. The correct answer is option “A” .

Note: Here, some of you may confuse in balancing the equation where numbers are written as subscript or sometimes in the front of molecules. So you can balance the equation by considering both numbers.