Is a neutralisation reaction a redox one ? For example;
NaOH +HCl=&gt;NaCl+H2O

<h2>Neutralization reactions</h2>
<div class="ns-school-defn2">
<h4>Fact:</h4>
<p>A <strong>cation</strong> is an ion (charged atom or molecule) with a positive (+) charge. An <strong>anion</strong> is an ion with a negative (-) charge.</p>
</div>
<div class="ns-school-defn2">
<h4>Fact:</h4>
<img alt="" src="https://data.ulearngo.com/assets/1024d5b4-3afa-4fb6-b094-ab82e164d42a"/>
<p>Salts are not just the table salt you put on your food. A salt is any compound made up of stoichiometrically equivalent amounts of cations and anions to make a neutral, <a data-lesson="ionic-solids" data-subject="chemistry" data-tutorial="liquids-and-solids" href="https://app.ulearngo.com/chemistry/liquids-and-solids/ionic-solids">ionic</a> compound.</p>
<img alt="" src="https://data.ulearngo.com/assets/5d8c9768-18e5-424f-baf9-d8c436d54a18"/>
<p>Magnesium sulfate heptahydrate ($\text{MgSO}_{4}.7\text{H}_{2}\text{O}$), commonly known as Epsom salt, can be used as a <a data-lesson="gels" data-subject="chemistry" data-tutorial="solutions-and-colloids" href="https://app.ulearngo.com/chemistry/solutions-and-colloids/gels">gel</a> to treat aches and pains, as bath salts, and has many other uses.</p>
</div>
<p>When an equivalent amount of acid and base react (so that neither the acid nor the base are in excess), the reaction is said to have reached the <strong>equivalence</strong> point. At this point <strong>neutralisation</strong> has been achieved.</p>
<div class="ns-school-emp">
<h3>Definition: Equivalence point</h3>
<div class="ns-school-defn">
<p>When a stoichiometrically equivalent number of moles of both reactants has been added to the reaction vessel.</p>
</div>
</div>
<p>To better understand stoichiometric equivalence look at the following equations:</p>
<ol>
<li>
<p>$1\color{red}{\text{HA(aq)}} + 1\color{blue}{\text{BOH(aq)}} \to$ $1\text{AB}(\text{aq}) + 1\text{H}_{2}\text{O}(\text{l})$</p>
</li>
<li>
<p>$1\color{red}{\text{H}_{2}{\text{A(aq)}}} + 2\color{blue}{\text{BOH(aq)}} \to$ $1\text{AB}_{2}(\text{aq}) + 2\text{H}_{2}\text{O}(\text{l})$</p>
</li>
</ol>
<p>In the first example above, a stoichiometrically equivalent number of moles is <strong>one</strong> mole of $\color{red}{\text{HA}}$ for every <strong>one</strong> mole of $\color{blue}{\text{BOH}}$. In the second example, a stoichiometrically equivalent number of moles is <strong>one</strong> mole of $\color{red}{\text{H}_{2}{\text{A}}}$ for every <strong>two</strong> moles of $\color{blue}{\text{BOH}}$.</p>
<div class="ns-school-emp">
<h3>Definition: Neutralisation</h3>
<div class="ns-school-defn">
<p>A neutralisation reaction involves an acid and a base reacting to form a salt.</p>
</div>
</div>
<p>Look at the following examples:</p>
<ul>
<li>
<p><strong>Hydrochloric acid with sodium hydroxide</strong></p>
<p>Hydrochloric acid reacts with sodium hydroxide to form sodium chloride (the salt) and water. Sodium chloride is made up of $\text{Na}^{+}$ cations from the base $(\text{NaOH})$ and $\text{Cl}^{-}$ anions from the acid $(\text{HCl})$.</p>
<p>$\text{H}{\color{red}{\textbf{Cl}}}{\text{(aq)}} + \color{blue}{\textbf{Na}}{\text{OH(aq)}} \to {\color{blue}{\textbf{Na}}}{\color{red}{\textbf{Cl}}}{\text{(aq)}} + {\text{H}}_{2}{\text{O(l)}}$</p>
</li>
<li>
<p><strong>Hydrogen bromide with postassium hydroxide</strong></p>
<p>Hydrogen bromide reacts with potassium hydroxide to form potassium bromide (the salt) and water. Potassium bromide is made up of $\text{K}^{+}$ cations from the base $(\text{KOH})$ and $\text{Br}^{-}$ anions from the acid $(\text{HBr})$.</p>
<p>$\text{H}{\color{red}{\textbf{Br}}}{\text{(aq)}} + \color{blue}{\textbf{K}}\text{OH(aq)} \to \color{blue}{\textbf{K}}\color{red}{\textbf{Br}}{\text{(aq)}} + {\text{H}}_{2}\text{O(l)}$</p>
</li>
<li>
<p><strong>Hydrochloric acid with sodium hydrocarbonate</strong></p>
<p>Hydrochloric acid reacts with sodium hydrocarbonate to form sodium chloride (the salt), water and carbon dioxide. Sodium chloride is made up of $\text{Na}^{+}$ cations from the base $(\text{NaHCO}_{3})$ and $\text{Cl}^{-}$ anions from the acid $(\text{HCl})$.</p>
<p>$\text{H}{\color{red}{\textbf{Cl}}}{\text{(aq)}} + {\color{blue}{\textbf{Na}}}{\text{HCO}}_{3}{\text{(aq)}} \to \color{blue}{\textbf{Na}}\color{red}{\textbf{Cl}}{\text{(aq)}} + {\text{H}_{2}{\text{O(l)}}} + {\text{CO}}_{2}{\text{(g)}}$</p>
</li>
</ul>
<p>You should notice that in the first two examples, the base contained $\text{OH}^{-}$ ions, and therefore the products were a <em>salt</em> and <em>water</em>. $\text{NaCl}$ (table salt) and $\text{KBr}$ are both salts. In the third example, $\text{NaHCO}_{3}$ also acts as a base, despite not having $\text{OH}^{-}$ ions. A salt is still formed as one of the products, but carbon dioxide ($\text{CO}_{2}$) is produced as well as water.</p>
<section>
<p>This experiment can be used for an informal assessment. It will help determine if the learners understand what happens in a neutralisation reaction. Learners are working with a strong acid and a strong base in this reaction. Concentrated, strong acids and bases can cause serious burns. Please remind the learners to be careful and wear the appropriate safety equipment when handling all chemicals, especially concentrated acids and bases. The safety equipment includes gloves, safety glasses, and protective clothing.</p>
</section>
<div class="ns-school-emp">
<h2>Optional Experiment: Temperature changes in neutralisation reactions</h2>
<div class="ns-school-defn">
<section class="activity">
<h3>Aim</h3>
<p>To investigate the temperature change associated with a neutralisation reaction.</p>
</section>
<section class="activity">
<h3>Apparatus</h3>
<ul>
<li>
<p>$\text{1}$ $\text{mol.dm$^{-3}$}$ solution of sodium hydroxide ($\text{NaOH}$), $\text{1}$ $\text{mol.dm$^{-3}$}$ solution of hydrochloric acid ($\text{HCl}$)</p>
</li>
<li>
<p>A thermometer, a beaker, a measuring cylinder</p>
</li>
</ul>
</section>
<section class="activity">
<h3>Method</h3>
<div class="ns-school-defn2 orange">
<h4>Warning:</h4>
<p>Concentrated acids and bases can cause serious burns. We suggest using gloves and safety glasses whenever you work with an acid or a base. Remember to add the acid to the water and to avoid sniffing any laboratory chemical. Handle all <a data-lesson="hazard-signs" data-subject="chemistry" data-tutorial="chemistry-essential-ideas" href="https://app.ulearngo.com/chemistry/chemistry-essential-ideas/hazard-signs">chemicals</a> with care.</p>
</div>
<ol>
<li>
<p>Pour $\text{20}$ $\text{cm$^{3}$}$ of the sodium hydroxide solution into the beaker.</p>
</li>
<li>
<p>Measure the temperature.</p>
</li>
<li>
<p>Add $\text{5}$ $\text{cm$^{3}$}$ of hydrochloric acid to the beaker using the measuring cylinder.</p>
</li>
<li>
<p>Repeat steps $\text{2}$ and $\text{3}$ quite quickly until the temperature no longer changes significantly.</p>
</li>
</ol>
</section>
<section class="activity">
<h3>Observations</h3>
<p>You should record your temperatures and the volume in a table (remember that the volume of the sodium hydroxide is constant at $\text{20}$ $\text{cm$^{3}$}$):</p>
<table>
<tbody>
<tr>
<td>
<p><strong>Volume (HCl)</strong></p>
</td>
<td>
<p><strong>Temperature (℃)</strong></p>
</td>
</tr>
<tr>
<td>
<p>$\text{0}$</p>
</td>
<td>
<p>room temperature</p>
</td>
</tr>
<tr>
<td> </td>
<td> </td>
</tr>
<tr>
<td> </td>
<td> </td>
</tr>
<tr>
<td> </td>
<td> </td>
</tr>
</tbody>
</table>
</section>
<section class="activity">
<h3>Discussion</h3>
<p>You should find that the reaction releases heat and so the temperature increases. After all the base has been neutralised the temperature should no longer increase. This is because the neutralisation reaction is <em>exothermic</em> (it releases heat). When all the base has been neutralised there is no reaction on the addition of more acid, and no more heat is released.</p>
</section>
<section>
<p>After the reaction has finished (the base has been neutralised) there is no more heat being produced. As a result the temperature will not rise any more. In fact, there may even be a decrease in temperature back to room temperature as the heat from the reaction vessel (the beaker) dissipates.</p>
</section>
</div>
</div>
<div class="ns-school-defn2">
<h4>Fact:</h4>
<p>Salts can come in many different colours.</p>
<img alt="" src="https://data.ulearngo.com/assets/7c29aa30-5b22-443f-aebb-ccedc5b490c7"/>
<p>$\color{purple}{\textbf{Potassium permanganate}}$ ($\color{purple}{\textbf{KMnO}_{4}}$)</p>
<img alt="" src="https://data.ulearngo.com/assets/e0148910-2f9d-478b-ab58-5155b2079499"/>
<p>$\color{blue}{\textbf{Copper sulfate}}$ ($\color{blue}{\textbf{CuSO}_{4}}$)</p>
<img alt="" src="https://data.ulearngo.com/assets/961c64c1-e5f2-4795-ac39-92a216aeb8ee"/>
<p>$\color{darkgreen}{\textbf{Nickel chloride}}$ ($\color{darkgreen}{\textbf{NiCl}_{2}}$)</p>
<img alt="" src="https://data.ulearngo.com/assets/8918c063-152a-4a9c-9fcf-e5759ed4d765"/>
<p>$\color{gold}{\textbf{Sodium chromate}}$ ($\color{gold}{\textbf{Na}_{2}{\textbf{CrO}}_{4}}$)</p>
<img alt="" src="https://data.ulearngo.com/assets/511658eb-dd61-417f-b19e-b7700347e19e"/>
<p>$\color{red}{\textbf{Potassim dichromate}}$ ($\color{red}{\textbf{K}_{2}{\textbf{Cr}}_{2}{\textbf{O}}_{7}}$)</p>
</div>
<p>Neutralisation reactions are very important in every day life. Below are some examples:</p>
<ul>
<li>
<p><strong>Domestic uses</strong></p>
<p>Calcium oxide $(\text{CaO})$ is used to neutralise acidic soil. Powdered limestone $(\text{CaCO}_{3})$ can also be used, but its action is much slower and less effective. These substances can also be used on a larger scale in farming and in rivers.</p>
</li>
<li>
<p><strong>Biological uses</strong></p>
<p>Hydrochloric acid $(\text{HCl})$ in the stomach plays an important role in helping to digest food. It is important to note that too much acid in the stomach may lead to the formation of ulcers in cases where the stomach lining is damaged (e.g. by an infection).</p>
<p><strong>Antacids</strong> (which are bases) are taken to neutralise excess stomach acid, to prevent damage to the intestines. Examples of antacids are aluminium hydroxide, magnesium hydroxide ('milk of magnesia') and sodium bicarbonate ('bicarbonate of soda').</p>
</li>
<li>
<p><strong>Industrial uses</strong></p>
<p>Alkaline calcium hydroxide (limewater) is used to absorb harmful acidic $\text{SO}_{2}$ <a data-lesson="non-ideal-gas-behavior" data-subject="chemistry" data-tutorial="gases" href="https://app.ulearngo.com/chemistry/gases/non-ideal-gas-behavior">gas</a> that is released from power stations and from the burning of fossil fuels.</p>
</li>
</ul>
<div class="ns-school-defn2 orange">
<h4>Warning:</h4>
<p>Please <strong>do not</strong> use a base to neutralise an acid if you spill some on yourself during an experiment. A strong base can burn you as much as a strong acid. Rather wash the area thoroughly with water.</p>
</div>
<div class="ns-school-defn2">
<h4>Fact:</h4>
<p>Bee stings are acidic and have a pH between $\text{5}$ and $\text{5.5}$. They can be soothed by using substances such as calomine lotion, which is a mild alkali based on <a data-lesson="chemical-reduction" data-subject="chemistry" data-tutorial="metals-metalloids-nonmetals" href="https://app.ulearngo.com/chemistry/metals-metalloids-nonmetals/chemical-reduction">zinc</a> oxide. Bicarbonate of soda, or soap, can also be used. The alkalis help to neutralise the acidic bee sting and relieve some of the itchiness.</p>
<img alt="" src="https://data.ulearngo.com/assets/50145939-c493-49f2-8631-3a79e70a66ab"/></div>

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Neutralization Reactions

Chemistry generally explores the substances of which matter is composed, the investigation of their properties and reactions, and the use of such reactions to form new substances. 

Chemistry

Discover how to define and identify acids and bases, understand conjugate acid-base pairs, and explore redox reactions with practical applications such as the production of chlorine and the chemistry of hair and hair products in this comprehensive chemistry tutorial.


Neutralization Reactions

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