Question

washing soda is used in removing permanent hardness of water.

what it's mean?​

Answer 1

Answer:

means making hard water soft means water is able to drink

Answer 2

Answer:

washing sodaHydrochloric acid reacts with sodium hydroxide to form sodium chloride (a salt) and water. Sodium chloride is made up of Na+ cations from the base (NaOH) and Cl− anions from the acid (HCl).

HCl (aq)+NaOH (aq)→H2O (l)+NaCl (aq)

Hydrogen bromide reacts with potassium hydroxide to form potassium bromide (a salt) and water. Potassium bromide is made up of K+ cations from the base (KOH) and Br− anions from the acid (HBr).

HBr (aq)+KOH (aq)→H2O (l)+KBr (aq)

Hydrochloric acid reacts with ammonia to form ammonium chloride (a salt). Ammonium chloride is made up of NH+4 cations from the base (NH3) and Cl− anions from the acid (HCl).

HCl (aq)+NH3(aq)→NH4Cl (aq)

You should notice that in the first two examples, the base contained OH− ions, and therefore the products were a salt and water. NaCl (table salt) and KBr are both salts. In the third example, NH3 also acts as a base, despite not having OH− ions. A salt is still formed as the only product, but no water is produced.

It is important to realise how useful these neutralisation reactions are. Below are some examples:

Domestic uses

Calcium oxide (CaO) is a base (all metal oxides are bases) that is put on soil that is too acidic. Powdered limestone (CaCO3) 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.

Limestone (white stone or calcium carbonate) is used in pit latrines (or long drops). The limestone is a base that helps to neutralise the acidic waste.

Biological uses

Acids in the stomach (e.g. hydrochloric acid) play an important role in helping to digest food. However, when a person has a stomach ulcer, or when there is too much acid in the stomach, these acids can cause a lot of pain. Antacids are taken to neutralise the acids so that they don't burn as much. Antacids are bases which neutralise the acid. Examples of antacids are aluminium hydroxide, magnesium hydroxide (“milk of magnesia”) and sodium bicarbonate (“bicarbonate of soda”). Antacids can also be used to relieve heartburn.

Industrial uses

Basic calcium hydroxide (limewater) can be used to absorb harmful acidic SO2 gas that is released from power stations and from the burning of fossil fuels.