10 mL of a solution of NaOH is found to be completely neutralised by 8 mL of a given solution of HCl. If we take 20 mL of the same solution of NaOH, - Science


10 mL of a solution of NaOH is found to be completely neutralised by 8 mL of a given solution of HCl. If we take 20 mL of the same solution of NaOH, the amount of HCl solution (the same solution as before) required to neutralise it will be:


  • 4 mL

  • 8 mL

  • 12 mL

  • 16 mL



16 mL


Since 10 mL of NaOH requires 8 mL of HCl, 20 mL of NaOH requires 8 × 2 = 16 mL of HCl.

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Chapter 2: Acids, Bases and Salts - Exercises [Page 34]


NCERT Science Class 10
Chapter 2 Acids, Bases and Salts
Exercises | Q 3 | Page 34

Video TutorialsVIEW ALL [2]


Dilute NaOH can be tested with
(a) red litmus paper
(b) blue litmus paper
(c) lime water
(d) Na2CO3

  Column A   Column B
i eosin 1 losing hydrogen
ii oxidation 2 synthetic indicator
    3 losing oxygen
    4 natural indicator


When phenolphthalein is added to NaOH, the colour of the solution will become _________.

  1. colourless
  2. red
  3. pink
  4. yellow

From which plant is litmus paper or litmus solution obtained?

  1. Moss
  2. Rose
  3. Hibiscus
  4. Lichen

What do we observe on pouring acetic acid on red and blue litmus papers?

(A) Red litmus remains red and blue litmus turns red.

(B) Red litmus turns blue and blue litmus remains blue.

(C) Red litmus turns blue and blue litmus turns red.

(D) Red litmus becomes colourless and blue litmus remains blue.

The litmus paper or the litmus solution is obtained from ________ plant

(A) Moss

(B) Lichen

(C) Rose

(D) Hibiscus

What happens when an acid reacts with a metal carbonate? Explain with the help of an example. Write chemical equation of the reaction involved.

A substance X which is used as an antacid reacts with dilute hydrochloric acid to produce a gas Y which is used in one type of fire-extinguisher. Name the substance X and gas Y. Write a balanced equation for the chemical reaction which takes place.

What ions are present in the solutions of following substances? (write the symbols only)

Magnesium hydroxide


What is the chemical formula of baking soda?

With which substance should chlorine be treated to get bleaching powder?

Phenolphthalein is a synthetic type of indicator.

Choose the correct alternative and rewrite the following sentence.

Phenolphthalein is ___________ type of indicator. 

When _______________ is passed through fresh lime water, it turns milky.

Answer the following question:
What is the universal indicator? Does Mg (OH)2 react with sodium hydroxide? If not, why?

With the help of suitable examples explain the term neutralization and the formation of –

  1. acidic,
  2. basic and
  3. neutral salts

Magnesium hydroxides are used for treating _______

Write any four physical properties of acids.

Acids turn blue litmus paper to ______.

What is a neutralization reaction? Give an example.

Egg shell is made up of ____________.

The table given below shows the reaction of a few elements with acids and bases to evolve Hydrogen gas.

Element Acid Base

Which of these elements form amphoteric oxides?

During the preparation of hydrogen chloride gas on a humid day, the gas is usually passed through the guard tube containing calcium chloride. The role of calcium chloride taken in the guard tube is to ______ 

Acids present in fruits and vegetables are called ______ acids.

A salt may be ______.

Solutions of acids conduct ______.

______ change the colour of the indicators.

Which acid is present in milk?

Can we taste acids and bases to identify them?

Copper or brass cooking vessels are coated with tin metal. Why?

Take a clean test tube with a holder and pour some dilute hydrochloric acid. Add a few pieces of magnesium ribbon pieces slowly. What do you observe? Now show a burning match stick near the mouth of the test tube. Do you hear any sound? The gas burns with a pop sound. From this, it is observed that hydrogen gas has been formed due to the reaction between acid and metal.

What is the correct procedure for mixing acid and water? Why?

“All acids contain one or more hydrogen atoms, but not all substances containing hydrogen are acids.” Support this statement with examples.

______ & ______ metals do not react with HCl or HNO3.

The formula of bleaching powder is  ______.

The taste of acid is ______.

Write notes on the properties of acids.

The metal that will not produce hydrogen gas when reacted with dilute acids.


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