Acids

Lactic acid(C3H6O3) is a fairly strong acid with a pH of 2.5, and is often the result of fermentation of sugar and can be found commonly in nature. Lactic acid in its pure form appears as a colourless or yellow odorless and syrupy liquid.

Vinegar(acetic acid)

Rice vinegar

White vinegar

Apple cider vinegar

Foods

Citrus(citric acid)

orange

Mandarin

Lemon

Lime

pomello

Mango(citric and malic acids)

Lactic acid

Milk

Tomatos(citric acid, malic acid, ascorbic acid, oxalic acid)

Spinach(nitric acid)

Carbonic acid

Soft drinks

Beer

Sparkling water

Dangerous acids

sulfuric acid

phosphoric acid

Medicine and manufacturing

Acetylsalicylic Acid

Pickled vegetables

Saurkraut

kimchi

fermented soy

Sourdough

wine

Ethanoic acid

hydrofluoric acid

olive oil(oleic acid, also in aerosol)

Litmus paper

What are some common household acids?

How could the acidity of household items be determined?

Carbonic acid (H2CO3)is acid that contains carbon, often formed by solutions of carbon dioxide in water. Carbonic acid is a fairly weak acid with a pH of around 3.8 and can be found in various organic settings, including as a respiratory acid inhaled by the human lungs, or in inorganic settings, such as in carbonated beverages.

The main component of vinegar, acetic acid(CH3COOH)is a fairly weak organic acid with a pH of 2.5 that is commonly found in food preservatives, cleaning products, fermentation process and vinegar, which is a dilute form of acetic acid(4-8% acetic acid) with flavourings.

Citric acid(C6H8O7) is a fairly weak organic acid with a pH of around 3-6 and is most commonly found in fruits of the citrus family, its powder form is used in cooking.

Apart from citric acid, there are many other types of acids that can be found in organic contexts, especially in fruits and vegetables. Some notable examples include tartaric acid (C4H6O6), malic acid (C4H6O5) and nitric acid(HNO₃).

Many acids such as sulfuric acid, formic acid, hydrofluoric acid(HF)and hydrochloric acid(HCl) are extremely acidic (0-1 pH), but can be used in dilute concentration for cleaning or in a scientific environment

Universal indicator

Acid-base titration

Method

Very limited in that it is only able to determine whether a substance is a base or acid, not how basic or acidic it is. However, it is an extremely simple and quick way of testing for pH.

Acid base titration, involving an indicator such as Phenolphthalein, can be used to determine the concentration and strength of an acid by slowly adding a base to an acid with the indicator and recording when the indicator indicates that the pH has changed (in the case of Phenolphthalein, when the measured solution has a pH of 9 or above.)8

Method

Dip a solution in litmus paper, which will turn red if the substance has a pH below 7(acid), or blue if the substance has a pH above 7(base)

This method of finding the pH can not only measure the concentration of acid within a substance but can do it in a controlled environment to limit external variables. However, it takes much longer with a lot more elaborate set up than the other methods, and like the universal indicator, requires visible colour change.

Method

The colour is dependent on the concentration and acidity of the added substance, which is an easy way to determine the pH of a substance. However, not only does the universal indicator not work on solids, but requires visible colours, which may be difficult for dark coloured substances like brown vinegar. Universal indicators also require precise control over the concentration and amount of tested substance, as well as indicator used

A universal indicator contains numerous dyes which, when exposed to a particular pH, will activate, and show that colour.