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Control and Coordination
Question
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Hard water is not available for an experiment. Some salts are given below :

(I) Sodium chloride

(II) Sodium Sulphate

(III) Calcium chloride

(IV) Calcium Sulphate

(V) Potassium chloride

(VI) Magnesium Sulphate

Select from the following group of these salts, each member of which may be dissolved in water to make it hard.

  • I, II, V

  • I, III, V

  • III, IV, VI

  • II, IV, VI

Answer

C.

III, IV, VI

Correct option is C.

Hard water contains sulphates, chlorides and bicarbonates of calcium and magnesium. So, calcium chloride, calcium sulphate and magnesium sulphate should be added in water to make it hard water. 

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Some More Questions From Control and Coordination Chapter

Give two physical characteristics each of acids and bases.

What are indicators? Name four acid-base indicators and mention their colour change.

What are antacids?

What are olfactory indicators?

You are given the following solutions:

Hydrochloric acid (HCl), sulphuric acid (H2SO4), nitric acid (HNO3), acetic acid (CH3COOH), sodium hydroxide (NaOH), calcium hydroxide [(Ca(OH)2], potassium hydroxide (KOH), magnesium hydroxide [Mg(OH)2] and ammonium hydroxide (NH4OH). Give the colour change for each of these solutions with red litmus, blue litmus, phenolphthalein and methyl orange solutions.

Choose the olfactory indicators and give their characteristics: red cabbage extract, onion, vanilla extract, litmus, clove oil.

What do you understand by concentrated and dilute acids?

How do metals react with bases?

What is a neutralization reaction? Give some examples.

What are non-metallic oxides? Substantiate your answer.