ACIDS, BASES AND SALTS

The correct way of making a solution of acid in water is to

• add water to acid.

• add acid to water.

• mix acid and water simultaneously.

• add water to acid in a shallow container.

Products of a neutralisation reaction are always

• an acid and a base.

• an acid and a salt.

• salt and water.

• a salt and a base.

Turmeric is a natural indicator. On adding its paste to acid and base separately, which colours would be observed

• Yellow in both acid and base.

• Yellow in acid and red in the base.

• Pink in acid and yellow in the base.

• Red in acid and blue in the base.

Phenolphthalein is a synthetic indicator and its colours in acidic and basic solutions, respectively are

• red and blue.

• blue and red.

• pink and colourless.

• colourless and pink

When the soil is too basic, plants do not grow well in it. To improve its quality what must be added to the soil?

• Organic matter

• Quick lime

• Slaked lime

• Calamine solution

‘Litmus’, a natural dye is an extract of which of the following?

• China rose (Gudhal)

• Beetroot

• Lichen

• Blueberries (Jamun)

A neutralisation reaction is a

• physical and reversible change.

• a physical change that cannot be reversed.

• chemical and reversible change.

• the chemical change that cannot be reversed.

A solution changes the colour of turmeric indicator from yellow to red. The solution is

• (a) basic

• (b) acidic

• (c) neutral

• (d) either neutral or acidic

Which of the following set of substances contain acids?

• Grapes, lime water

• Vinegar, soap

• Curd, milk of magnesia

• Curd, vinegar

On adding phenolphthalein indicator to a colourless solution, no change is observed. What is the nature of this solution?

• Basic

• Either acidic or basic

• Either acidic or neutral

• Either basic or neutral