Common Acids and Alkalis Overview

Acids are substances that taste sour and are found in various foods and drinks like orange juice, lemon, vinegar, and yoghurt. They are also present in some household products like hair conditioner, lotion, and toilet cleaner.

Alkalis are substances that often have a bitter taste and a slippery feel. They are found in foods like Chinese noodles, lye water rice dumplings, and preserved duck eggs. Alkalis are also present in many household products, including kitchen cleaner, bleach, alkaline batteries, toothpaste, and soap.

Ethanoic acid, also known as acetic acid, is the main component of vinegar, giving it its characteristic sour taste.

Hydrochloric acid, sulphuric acid, and nitric acid are common acids used in laboratories for various experiments and chemical reactions.

Acids and alkalis can be corrosive and harmful if mishandled. Always handle them with care and never directly taste them, especially those found in cleaning products.

Many acids and alkalis are used in everyday household products but can cause skin irritation or even burns if mishandled. It's important to be cautious while using these products and wear protective gear if necessary.

Acids have a sour taste, while alkalis give a slippery feel. Some alkalis may also have a bitter taste. These properties help distinguish acids from alkalis.

Acids and alkalis are important chemicals used in various applications, including food, cleaning, and laboratory experiments. It's important to understand their characteristics and handle them safely.

Vinegar, a common household acid, is used to preserve vegetables by inhibiting bacterial growth and creating a sour taste.

Hydrochloric acid, a strong acid found in toilet cleaners, reacts with dirt and stains to break them down, making them easier to flush away.

Lye water, an alkaline solution, is added to Chinese noodles during production to make them chewy by strengthening the gluten network.

Sodium hydroxide, a strong alkali found in kitchen cleaners, reacts with grease and fats, breaking them down and allowing them to be easily wiped away.

Acids and alkalis are substances with distinct chemical properties that make them useful in various applications, from food preservation to cleaning.

Strong acids, like hydrochloric acid, sulfuric acid, and nitric acid, are commonly found in laboratories.

Nitric acid, a corrosive acid, is easily decomposed by light and should be stored in dark-colored bottles to prevent degradation.

Sodium hydroxide, ammonia solution, and calcium hydroxide (lime water) are common alkalis found in laboratories.

Acids and alkalis are often irritants or even corrosive, requiring safety precautions for safe handling in a laboratory environment.

Always read the hazard warning symbols on chemical bottles before handling them to understand the risks involved.

When working with acids and alkalis, wear protective equipment, such as a lab coat, gloves, and safety glasses, to minimize exposure.

Never mix acids or alkalis with other chemicals without getting permission from a qualified instructor.

Dispose of waste solutions into designated waste bottles, never down the sink, as these chemicals can harm pipes and the environment.

Red cabbage extract shows different colors in acidic and alkaline solutions, making it a useful indicator to distinguish between acids and alkalis.

The pigment in red cabbage extract changes color depending on the pH of the solution.

Butterfly pea flower extract is blue in neutral solutions, turns purple in acids, and changes to blue-green in alkaline solutions.

Red onion skin extract is light brown in neutral solutions, turns orange in acids, and changes to brown-green in alkaline solutions.

Some natural substances can be used to test whether a solution is acidic or alkaline, just like litmus paper.

Plants can be used as natural indicators to distinguish between acids and alkalis.

Vinegar belongs to the class of substances called acids.

Soap solution belongs to the class of substances called alkalis.

Substances in nature that change color when in contact with acids or alkalis, helping to identify them.

A natural indicator is used in this practical to show the color change in acidic and alkaline solutions.

A solution with a pH less than 7, often sour, and can react with metals.

A solution with a pH greater than 7, often slippery and bitter.

Red cabbage extract is an example of a natural indicator. It turns red in acidic solutions and blue-green in alkaline solutions.

Distilled water is neither acidic nor alkaline. It has a neutral pH of 7.

Lemon juice is acidic, having a pH less than 7. It turns red cabbage extract red.

Baking soda solution is alkaline, having a pH greater than 7. It turns red cabbage extract blue-green.

Plant extracts can be used to identify acids and alkalis. These natural indicators change color depending on whether they are in an acidic or alkaline solution.

Litmus is a common indicator in the laboratory. It is a mixture of pigments from lichens. There are two types: blue litmus and red litmus.

Blue litmus turns red in an acidic solution, while red litmus remains red.

Blue litmus remains blue in an alkaline solution, while red litmus turns blue.

In neutral solutions, both blue and red litmus remain unchanged.

Hydrangeas are a great example of how pH can affect color. In acidic soil, they bloom blue, but in alkaline soil, they turn pink.

Using baking soda solution and blueberry extract, write a secret message that becomes invisible and can later be revealed.

The secret message appears because blueberry extract acts as a natural indicator. When the extract is applied to the baking soda solution, a color change occurs.

Universal indicator is a mixture of dyes that changes color depending on the pH of the solution.

A pH meter is an electronic device that measures the pH of a solution by measuring the electrical potential difference between two electrodes.

Universal indicator is a solution that is simple to use, requiring no calibration.

Universal indicator is not suitable for dark-colored solutions because the color change may be difficult to observe.

A pH meter is more accurate than universal indicator because it can provide a numerical reading of the pH value.

A pH meter requires calibration before use to ensure accurate readings.

A pH meter is suitable for solutions of any color, allowing for accurate pH measurements even in dark-colored solutions.

A pH meter can be reused after proper cleaning and calibration.

A measurement scale ranging from 0 to 14 that indicates the acidity or alkalinity of a substance.

Substances with a pH less than 7, having a sour taste. The lower the pH value, the more acidic the substance.

Substances with a pH greater than 7, often having a bitter taste and a slippery feel. The higher the pH value, the more alkaline the substance.

A type of universal indicator available in paper form. It is used for testing the approximate pH value of substances.

Provides a reference to match the colors produced by universal indicator or pH paper to their corresponding pH values.

It is a procedure involving testing the pH values of different substances using pH paper and universal indicator.

The pH value of a substance is measured using pH paper or universal indicator by correlating the color changes to the values on a pH color chart.

A substance with a pH of 7 is considered neutral. This means it is neither acidic nor alkaline. Distilled water is a good example of a neutral substance.

Lemon juice is more acidic than apple juice, meaning it has a lower pH value. This explains the difference in taste and the different colors produced when tested with a pH indicator.

Oven cleaner is a strong alkali, meaning it has a high pH value. This makes it effective at removing grease and grime but also requires caution due to its corrosive properties.

Neutralization is a chemical reaction where an acid and an alkali react to form salt and water, resulting in a more neutral solution with a pH closer to 7.

The pH value is a measure of how acidic or alkaline a solution is. A pH value below 7 indicates acidity, while a pH above 7 indicates alkalinity. A pH of 7 is considered neutral.

During neutralization, the pH value of the solution changes as the acid and alkali react. The pH of an acidic solution increases towards 7 as it becomes less acidic. The pH of an alkaline solution decreases towards 7 as it becomes less alkaline.

In the experiment, dilute hydrochloric acid (an acid) is mixed with dilute sodium hydroxide (an alkali). As they react, the solution becomes less acidic or alkaline, and the pH value shifts closer to 7, which is neutral. You can visually see this change with the universal indicator.

A magnetic stirrer is a lab device used to mix solutions. It has a rotating magnet that spins a stir bar placed in the solution, creating a swirling motion and ensuring even mixing.

The pH value of the resulting solution increases slowly as dilute sodium hydroxide solution is added to dilute hydrochloric acid.

The pH value increases sharply just before and after the resulting solution reaches pH 7.

The pH value further increases and levels off at about pH 13 when more dilute sodium hydroxide solution is added after the resulting solution reaches pH 7.

When the pH value of the resulting solution reaches 7, the solution becomes neutral. This means the acid and alkali have neutralized each other.

10 cm3 of dilute sodium hydroxide solution is needed to neutralize 10 cm3 of dilute hydrochloric acid.

The temperature of the resulting solution increases to a maximum and then decreases during a neutralization reaction.

A data logger connected to a pH sensor works like a pH meter and can even record the changes in the pH value of a solution over time.

The data logger with a temperature sensor records the temperature changes in the solution during the neutralization reaction.

Thermal energy is released during the reaction between an acid and an alkali.

During neutralization, an acid and an alkali react to form salt and water. The resulting solution becomes less acidic or alkaline.

A salt is formed when an acid and an alkali neutralize each other. This salt can be a solid or a dissolved substance.

When an acid and an alkali react, they neutralize each other. The pH value of the solution becomes closer to 7, which is neutral.

A conical flask is a common laboratory glassware used for holding and mixing liquids. It has a wide base and a narrow neck that helps in preventing spills and evaporation.

A Bunsen burner is a laboratory equipment used for heating. It produces a hot, controlled flame for experiments.

A watch glass is a shallow, circular piece of glass used in laboratories for holding small samples, evaporating liquids, or covering beakers.

A substance that is neither acidic nor alkaline, having a pH of 7. An example is distilled water.

A substance with a pH less than 7, typically having a sour taste. Examples include lemon juice, vinegar, and hydrochloric acid.

A substance with a pH greater than 7, often having a bitter taste and a slippery feel. Examples include baking soda solution, soap solution, and sodium hydroxide.

A pure substance formed when two or more elements chemically combine in a fixed ratio. Examples include salt (sodium chloride) and water (hydrogen oxide).

A mixture is a combination of two or more substances where each substance retains its own properties. Examples include salt water, sand and water, and air.

A change where no new substances are formed, just a change in appearance or state. Examples include melting ice, boiling water, or dissolving sugar.

A change where new substances are formed with different properties. Examples include burning wood, rusting iron, or neutralization.

The type of salt formed depends on the specific acid and alkali used.

The first part of the salt's name comes from the alkali, and the second part comes from the acid.

The process of mixing an acid and an alkali until the solution becomes neutral, with a pH of 7.

The heat released during a neutralization reaction.

The pH of a solution changes during neutralization, becoming closer to 7.

The amount of heat released in a neutralization reaction depends on the specific substances used and their concentrations.