(a) What is a salt? Give the names and formulae of any two salts. Also name the acids and bases from which these salt may be obtained.
(b) What is meant by 'a family of salts'? Explain with examples.
(c) What is meant by 'hydrated' and 'anhydrous' salts? Explain with examples.
(d) Write the names, formulae and colours of any two hydrated salts.
(e) What will be the colour of litmus in an aqueous solution of ammonium chloride salt?

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Solution

Salt is a compound formed when a metal replaces the hydrogen atom in an acid. The names and formulae of two salts are sodium chloride, NaCl, and ammonium chloride, NH₄Cl, respectively. Sodium chloride salt (NaCl) is formed from an acid, hydrochloric acid (HCl), and a base (NaOH). Ammonium chloride (NH₄Cl) is formed from an acid, hydrochloric acid (HCl), and a base, ammonium hydroxide (NH₄OH).

Salts having the same positive ions or the same negative ions belong to one family of salts. For example, calcium chloride (CaCl₂) and calcium sulphate (CaSO₄) belong to the same family of salts called ‘calcium salts’ because they both contain the same positively charged ions, calcium ions (Ca²⁺). Similarly, zinc sulphate (ZnSO₄) and copper sulphate (CuSO₄) belong to the same family of salts called ‘sulphate salts’ because they both contain the same negatively charged ions, sulphate ions (SO₄^2-).

Salts that contain water of crystallisation are called ‘hydrated salts’. For example, copper sulphate crystals contain five molecules of water of crystallisation in one formula unit and hence is written as CuSO₄.5H₂O. It is also called copper sulphate pentahydrate.

Salts that have lost their water of crystallisation on heating are called ‘anhydrous salts’. For example, when copper sulphate crystals (CuSO₄.5H₂O), which are blue, are heated strongly, they lose all the water of crystallisation and form anhydrous copper sulphate (CuSO₄), which is white.

Hydrated salts:

Copper sulphate pentahydrate crystals, CuSO₄.5H₂O, are blue.

Iron sulphate heptahydrate crystals, FeSO₄.7H₂O, are green.

Blue litmus turns red. NH₄Cl is formed from a weak base, ammonium hydroxide (NH₄OH), and a strong acid, hydrochloric acid (HCl). So, on dissolving in water, NH₄Cl will hydrolyse to form more H⁺ ions than OH^- ions, and thus it is acidic.

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Similar questions

1) what is a salt? Give the names and formula of any two salts. Also name the acids and bases from which these salts may be obtained?

2) what is meant by hydrated and anhydrous salts.give examples.

3) write the names formulae and colours of any two hydrated salts.

Two metals X and Y form the salts $X S O_{4}$ and $Y_{2} S O_{4}$ , respectively. The solution of salt $X S O_{4}$ is blue in colour whereas that of $Y_{2} S O_{4}$ is colourless. When barium chloride solution is added to $X S O_{4}$ solution, then a white precipitate Z is formed along with a salt which turns the solution green. And when barium chloride solution is added to $Y_{2} S O_{4}$ solution, then the same white precipitate Z is formed along with colourless common salt solution.

(a) What could the metal X and Y be ?

(b) Write the name and formula of salt $X S O_{4}$ .

(d) What is the name and formla of white precipitate Z ?

(e) Write the name and formula of the salt which turns the solution green in the first case.

Q. Two metals X and Y form the salts XSO₄ and Y₂SO₄, respectively. The solution of salt XSO₄ is blue in colour whereas that of Y₂SO₄ is colourless. When barium chloride solution is added to XSO₄ solution, then a white precipitate Z is formed alongwith a salt which turns the solution green. And when barium chloride solution is added to Y₂SO₄ solution, then the same white precipitate Z is formed alongwith colourless common salt solution.
(a) What could the metals X and Y be?
(b) Write the name and formula of salt XSO₄.
(c) Write the name and formula of salt Y₂SO₄.
(d) What is the name and formula of white precipitate Z?
(e) Write the name and formula of the salt which turns the solution green in the first case.

Q. When a blue coloured copper salt is heated strongly, it forms a white copper salt. The white copper salt can be reconverted into blue copper salt by adding a liquid X.
(a) Write the formula of blue copper salt.
(b) Write the formula of white copper salt.
(c) What substance is lost when blue copper salt is converted into white copper salt?
(d) Name the liquid X.

Which of the following formula and colour is/are correct for hydrated salts:-

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