Q. \[ \mathrm{HCl} + \mathrm{NaOH} \rightarrow \mathrm{NaCl} + \mathrm{H}_2\mathrm{O} \]
Answer
Neutralization of hydrochloric acid with sodium hydroxide produces sodium chloride and water. Balanced molecular equation:
\[
\mathrm{HCl\,(aq)} + \mathrm{NaOH\,(aq)} = \mathrm{NaCl\,(aq)} + \mathrm{H_2O\,(l)}
\]
Complete ionic equation:
\[
\mathrm{H^+\,(aq)} + \mathrm{Cl^-\,(aq)} + \mathrm{Na^+\,(aq)} + \mathrm{OH^-\,(aq)} = \mathrm{Na^+\,(aq)} + \mathrm{Cl^-\,(aq)} + \mathrm{H_2O\,(l)}
\]
Net ionic equation:
\[
\mathrm{H^+\,(aq)} + \mathrm{OH^-\,(aq)} = \mathrm{H_2O\,(l)}
\]
Detailed Explanation
We are asked to react hydrochloric acid with sodium hydroxide. This is a simple acid–base neutralization. The balanced molecular equation is shown below.
\[ \mathrm{HCl} + \mathrm{NaOH} = \mathrm{NaCl} + \mathrm{H_{2}O} \]
Step 1. Identify reactants and products. Hydrochloric acid, \( \mathrm{HCl} \), is a strong acid. Sodium hydroxide, \( \mathrm{NaOH} \), is a strong base. The products of their neutralization are sodium chloride, \( \mathrm{NaCl} \), and water, \( \mathrm{H_{2}O} \).
Step 2. Balance the equation by counting atoms on each side. Count hydrogen, chlorine, sodium and oxygen atoms.
– Left side: hydrogen atoms: \(1\) from \( \mathrm{HCl} \) and \(1\) from \( \mathrm{NaOH} \), total \(2\). Chlorine atoms: \(1\). Sodium atoms: \(1\). Oxygen atoms: \(1\).
– Right side: hydrogen atoms: \(2\) in \( \mathrm{H_{2}O} \). Chlorine atoms: \(1\) in \( \mathrm{NaCl} \). Sodium atoms: \(1\) in \( \mathrm{NaCl} \). Oxygen atoms: \(1\) in \( \mathrm{H_{2}O} \).
All atom counts match, so the equation as written is balanced. All stoichiometric coefficients are \(1\).
Step 3. Write the ionic forms because both acid and base are strong electrolytes and fully dissociate in water. The complete ionic equation is
\[ \mathrm{H^{+}} + \mathrm{Cl^{-}} + \mathrm{Na^{+}} + \mathrm{OH^{-}} = \mathrm{Na^{+}} + \mathrm{Cl^{-}} + \mathrm{H_{2}O} \]
Step 4. Cancel spectator ions. The sodium ion, \( \mathrm{Na^{+}} \), and the chloride ion, \( \mathrm{Cl^{-}} \), appear on both sides and are spectators. Removing them yields the net ionic equation.
\[ \mathrm{H^{+}} + \mathrm{OH^{-}} = \mathrm{H_{2}O} \]
Step 5. Stoichiometry and example. The mole ratio is \(1\) mole \( \mathrm{HCl} \) reacts with \(1\) mole \( \mathrm{NaOH} \) to give \(1\) mole \( \mathrm{NaCl} \) and \(1\) mole \( \mathrm{H_{2}O} \). For example, if you mix \(0.100\) mol \( \mathrm{HCl} \) with \(0.100\) mol \( \mathrm{NaOH} \), you will produce \(0.100\) mol \( \mathrm{NaCl} \) and \(0.100\) mol \( \mathrm{H_{2}O} \).
Step 6. pH result. When equimolar amounts of a strong acid and a strong base are mixed, the resulting solution is neutral (pH about \(7\) at \(25^\circ\mathrm{C}\) ). Sodium chloride is a neutral salt and does not hydrolyze to change the pH in this ideal case.
Chemistry FAQs
What type of reaction is \( \mathrm{HCl} + \mathrm{NaOH} \) ?
What is the stoichiometric mole ratio between \( \mathrm{HCl} \) and \( \mathrm{NaOH} \) ?
How do I calculate the volume of \( \mathrm{NaOH} \) needed to neutralize given volume of \( \mathrm{HCl} \) ?
How do I find the pH after mixing \( \mathrm{HCl} \) and \( \mathrm{NaOH} \) ?
What is the net ionic equation for the reaction?
What salt forms and what are its properties in solution ?
How do I calculate the concentration of the produced \( \mathrm{NaCl} \) solution ?
What if pH is < 7 or > 7 after mixing ?
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