Exemplar Problems
Problem 13 : The balanced chemical equation for the reaction between sodium (Na) and water (H₂O) to form sodium hydroxide (NaOH) and hydrogen gas (H₂) is:
[2Na + 2H₂O → 2NaOH + H₂]
Solution :
Step 1: Write down the unbalanced chemical equation for the reaction:
Na + H₂O → NaOH + H₂
Step 2: Begin by balancing the hydrogen (H) atoms. There are 2 hydrogen atoms on the left side (in H₂O) and 2 hydrogen atoms on the right side (in H₂ and NaOH), so the hydrogen atoms are already balanced.
Step 3: Next, balance the sodium (Na) atoms. There is 1 sodium atom on the left side (in Na) and 1 sodium atom on the right side (in NaOH), so the sodium atoms are balanced as well.
Step 4: Now, check if the oxygen (O) atoms are balanced. On the left side, there are 2 oxygen atoms (in H₂O), and on the right side, there are 2 oxygen atoms (in NaOH). So, the oxygen atoms are balanced.
Step 5: The equation is already balanced for all the elements, but it’s a good practice to ensure that the coefficients (numbers in front of the chemical formulas) are in the simplest whole number ratio. In this case, they are:
Na + H₂O → NaOH + H₂
So, the final balanced chemical equation is:
[Na + H₂O → NaOH + H₂]
This equation represents the reaction between sodium and water to form sodium hydroxide and hydrogen gas, and it is now balanced.