Why does an acid solution make a purple litmus solution turn red?

Reddening refers to the formation of a reddish pigment when it meets acid, and the microscopic does not need to be considered, which is a characteristic, thank you.

It shows that the molecules are constantly moving, absolutely so, I remember the chemistry teacher before.

It is the hydrogen ions in the acid that make it red.

The chemical equation for purple litmus to turn red is: co + h o = h co, carbon dioxide reacts with water to form carbonic acid to turn purple litmus solution red. Litmus is a complex organic compound with a complex structure that is difficult to write about.

The purple litmus test solution turns red when it encounters acid, and generally only describes the phenomenon.

Both litmus and phenolphthalein are acid-base indicators, and they are a weak organic acid. In solution, as the acidity and alkalinity of the solution change, the molecular structure of the indicator changes and shows different colors.

Limus is a weak organic acid with a relative molecular weight of 3300, which changes its conjugate structure and changes color under the different actions of acid-base solutions.

The principle of litmus changing color is: hin

Reversible = h++

With the change of acidity and alkalinity of the solution, its molecular structure changes and presents different color changes(1) In acidic solution, molecules are the main form of its existence, making the solution red; (The balance shifts to the left due to the increase in [h+]).

2) In the alkaline solution, the ionization equilibrium of litmus hydrolysis shifts to the right, and the acid ions produced by ionization are the main form of its existence, so the solution is blue with long and short intestines. (The balance shifts right due to the increase in [oh-]).

3) In a neutral solution, molecules and acid ions coexist, so the solution is purple.

The color-changing pH range of litmus is: 5 8, red when the solution pH < 5, blue when pH >8, and purple when pH 5 8.

Hope it helps.

Purple litmus is an indicator that turns from purple to red when encountering an acidic solution and blue when encountering an alkaline reagent

The purple litmus test solution turns red when it is acid, and blue when it is alkaline.

The litmus solution turns red when exposed to acid. When exposed to alkali, it turns blue. Note that acid or alkali solutions can discolor purple litmus solutions or colorless phenolphthalein solutions, while acids or bases that are insoluble in water cannot discolor the indicator. For example, copper hydroxide cannot make a purple litmus solution turn blue.

The hydrogen ions dissociated from the acid itself can turn red by reacting with litmus, and litmus can turn red as long as the acidity of the acid is stronger than that of litmus.

Litmus itself is also a mixed solution of weak acid and alkali, when encountering a strong acidic substance, litmus forms the form of acid molecules, which is red, and when encountering a strong alkaline substance, in the form of a weak acid root, it appears blue.

The same is true for other acid-base indicators, different acidity and alkalinity, different forms of existence of weak acid-base, different colors, of course, the pH value of different indicators is different, such as litmus, phenolphthalein, methyl orange, methyl red and so on.

Acids can work with acid-base indicators!!

Can make purple litmus solution red!

Colorless phenolphthalein does not change color!

Purple litmus solution is a common chemical in chemical experiments, which is usually used to test the acidity and alkalinity of the solution. Purple litmus solution is generally made by mixing distilled water and litmus powder, and at room temperature and pressure, the purple litmus solution will appear purple. The purple litmus solution is dropped into the solution to be tested, and the reaction phenomenon can be found after the reaction phenomenon appears, and the purple litmus solution turns red when it is acid, and it turns blue when it is alkaline.