what turns red litmus blue?

Answer 1

Red litmus paper turns blue under base (i.e. alkaline) conditions. In chemistry, a base is most commonly thought of as a substance which can accept protons. This refers to the Bronsted-Lowry theory of acids and bases. Alternate definitions of bases include electron pair donors (Lewis), and as sources of hydroxide anions (Arrhenius). Examples of simple bases are sodium hydroxide and ammonia.

Bases can be thought of as the chemical opposite of acids. A reaction between an acid and base is called neutralization. Bases and acids are seen as opposites because the effect of an acid is to increase the hydronium ion (H3O+) concentration in water, where as bases reduce this concentration. Bases react with acids to produce water and salts (or their solutions). Some general properties of bases include:

- Taste: Bitter taste (opposed to sour taste of acids and sweetness of aldehydes and ketones)
- Touch: Slimy or soapy feel on fingers
- Reactivity:Caustic on organic matter, react violently with acidic or reducible substances
- Electric conductivity: Aqueous solutions or molten bases dissociate in ions and conduct electricity

A strong base is a base which hydrolyzes completely, raising the pH of the solution towards 14. Strong bases, like strong acids, attack living tissue and cause serious burns. They react differently to skin than acids do so while strong acids are corrosive, we say that strong bases are caustic. Superbases are a class of especially basic compounds and harpoon bases are a special class of strong bases with poor nucleophilicity. Bases may also be weak bases such as ammonia, which is used for cleaning. Arrhenius bases are water-soluble and these solutions always have a pH greater than 7. An alkali is a special example of a base, where in an aqueous environment, hydroxide ions are donated. There are other more generalized and advanced definitions of acids and bases.

The notion of a base as a concept in chemistry was first introduced by the French chemist Guillaume François Rouelle in 1754. He noted that acids which in those days were mostly volatile liquids (like acetic acid) turned into solid salts only when combined with specific substances. These substances form a concrete base for the salt and hence the name.

Answer 2

alkali which is also known as base turns red litmus paper blue.
while acid turns blue litmus paper red. judging by experiment and pH values too, on the scale of ---
acidity- 1 2 3 4 5 6
alkalinity- 8 9 10 11 12 13 14
7 is the neutral so you also determine by using a pH scale besides litmus paper even though litmus is the easiest, fastest and surest way.

Answer 3

When litmus is extracted from lichens, its natural colour is actually blue. The active constituent of litmus is azolitmin, which is a polyhydric phenol. In acidic solution, the azolitmin changes to the cationic (i.e. positively charged) form, which has a different structure from the natural form and it is therefore not surprising that it should have a different colour - the cationic form is, in fact red. Unlike synthetic indicators, which change over a very narrow pH range, the change in the case of azolitmin is gradual and takes place over the range 8·0 (blue) to 5·0 (red) (i.e. very weakly alkaline to weakly acidic). If you add alkali to the red form, its pH will rise above 8 and it will revert to the natural, blue colour.

Answer 4

Alkalis turn red litmus blue

Acids turn blue litmus red

Answer 5

Litmus is a weak acid, already described by someone else here how and from where it is obtained.

In simple terms the un-ionised litmus is red, whereas the ion is blue.

Please check the URL I have listed as my source as it covers litmus, and other indicators in further detail.

Answer 6

red litmus can be turned blue by using a base

Answer 7

Calcium Hydroxide is a base. It will turn red litmus paper blue, as it is a base. Grp 2 metals are alkaline(bases)

Answer 8

Any base in solution (an Alkali) .
It must have a pH greater than 7(seven).

Answer 9

a substance with a pH greater than 7 e.g sodium hydroxide

Answer 10

a base