Class 10 Science Chapter 2 MCQ

Class 10 Science Chapter 2 MCQ (Multiple Choice Questions) of Acids, Bases and Salts. All the MCQs are taken from NCERT Textbooks issued for session 2020-2021. Answers and explanation of MCQ tests are given just below each questions.

MCQs are important for the CBSE and other boards final exams. It also clears the concepts about Acids, Bases and salts. So, practice here with MCQ test and prepare for school exams and board exams.

Class 10 Science Chapter 2 MCQ with Answers

Class: 10 Science
Chapter: 2MCQ (Multiple Choice Questions) test

Class 10 Science Chapter 2 MCQ Test 2020-2021

CBSE Class 10 Science Chapter 2 MCQ tests with answer and complete explanation of each answer. MCQs are important for most of the boards like UP Board, Bihar Board, MP Board as well as CBSE board. So, prepare your chapter with the following 20 sets of MCQs containing about 100 questions.


Which of the following statement is or are incorrect?

[A]. Our body works well within a narrow pH range of 7.0 to 7.8.
[B]. When the pH of rain water is about 5.6, it is called acid rain.
[C]. If the soil is too acidic (having low pH), then it is treated with materials like quicklime (calcium oxide) or slaked lime (calcium hydroxide) or chalk (calcium carbonate).
[D]. Most of the plants grow best when the pH of the soil is close to 4.

Consider the following statement and choose the incorrect one:

[A]. Pure water is neutral, the concentrations of hydrogen ions and hydroxide ions are equal.
[B]. Acidic solutions have excess of hydrogen ions.
[C]. The basic solutions have excess of hydroxide ions.
[D]. A solution having a high concentration of hydrogen ions has a high pH value.


Mohan is writing some statements, choose the incorrect statements and help him:

[A]. In the absence of water, a substance will not form hydrogen ions and hence will not show its acidic behaviour.
[B]. Hydrochloric acid is completely ionised in water, so it is a weak acid.
[C]. Dry, HCl gas does not change the colour of dry blue litmus paper because it has no hydrogen ions.
[D]. The HCl gas turns ‘wet’ blue litmus paper red because it dissolves in the water present in wet litmus paper to form hydrogen ions.

Which one of the following can be used as an acid-base indicator by a visually impaired student?

[A]. Litmus
[B]. Turmeric
[C]. Vanilla essence
[D]. Petunia leaves

Parmindar is writing some statements about polyester. In which of the following statements is or are incorrect? Help him.

[A]. Dilute hydrochloric acid reacts with copper (II) oxide to form copper (II) chloride and water.
[B]. Acids are never stored in metal containers or glass and ceramics because they gradually corrode and eat up the metal container.
[C]. The reaction between acids and metal oxides is a kind of “Neutralization reaction”.
[D]. Milk of Magnesia is a metal hydroxide called ‘magnesium hydroxide’ which is used to remove indigestion caused too much hydrochloric acid in the stomach.

In a science exam, you are asked a question where you have to choose the statement which is/ are incorrect?

[A]. Curd and other sour foodstuffs such as vinegar, lemon juice and orange juice, etc., should not be kept in metal vessels like copper vessels.
[B]. If someone is suffering from the problem of acidity after over eating, we can suggest taking baking soda solution as remedy.
[C]. Egg-shells, limestone, marble and chalk are the different forms calcium carbonate.
[D]. None of the above


Sukhvir appeared in test of class 10th standard, where he wrote some statements but he confused to know the incorrect statement. Would you help him to know that?

[A]. A concentrated acid is one which contains the minimum possible amount of water in it.
[B]. A dilute acid is one which contains the much more amount of water in it.
[C]. When water is added to concentrated acid to dilute it then the heat is evolved gradually.
[D]. None of them

Sodium hydrogen carbonate, when added to acetic acid, evolves a gas. Which of the following statements are true about the gas evolved?

[A]. It turns lime water milky, and it extinguishes a burning splinter.
[B]. It turns lime water milky, and it extinguishes a burning splinter, and it dissolves in a solution of sodium hydroxide.
[C]. It extinguishes a burning splinter, it dissolves in a solution of sodium hydroxide, and it has a pungent odour.
[D]. It turns lime water milky, and it has a pungent odour.

Consider the following statement and choose the incorrect one:

[A]. An indicator is a dye that changes colour when it is put into an acid or a base.
[B]. The most common indicators to test for acids and bases are litmus, methyl orange and phenolphthalein.
[C]. The most common indicator used for testing acids and bases in the laboratory is phenolphthalein.
[D]. None of the above

Sodium carbonate is a basic salt because it is a salt of:

[A]. Strong acid and strong base
[B]. Weak acid and weak base
[C]. Strong acid and weak base
[D]. Weak acid and strong base

Find the correct answer of MCQ

Consider the following statements and choose the incorrect one:

    • [A] The red cabbage extract is also a natural indicator.
    • [B] The red cabbage extract remains red in acidic solution, but turns green on adding two basic solution.
    • [C] Those substances whose smell changes in acidic or basic solution are called olfactory indicators.
    • [D] The smell of the onion cannot be detected when it is added to an acidic solution.

Explanation: Onion has a characteristic smell. An acidic solution like hydrochloric acid, does not destroy the smell of onions. When a basic solution like sodium hydroxide solution is added to a cloth strip treated with onions, then the onions smell cannot be detected.

Find the correct answer of MCQ

A sample of soil is mixed with water and allowed to settle. The clear supernatant solution turns the pH paper yellowish-orange. Which of the following would change the colour of this pH paper to greenish-blue?

    • [A] Lemon Juice
    • [B] Vinegar
    • [C] Common salt
    • [D] An antacid

Explanation: Lemon juice is primarily a rich source of vitamin C which is citric acid.
Vinegar is a mixture of acetic acid and water. It is produced by acid acting bacteria. It is a mild acid.
Common salt is sodium chloride which has sodium ions and chloride ions. So, these three cannot change the pH paper to greenish blue as only base can bring this change.
Antacid is a base which is baking soda or sodium bicarbonate or sodium hydrogen carbonate which can change the pH paper from yellow orange to green while others are acidic in nature.

Calcium phosphate is present in tooth enamel. Its nature is [A] Basic [B] Acidic [C] Neutral [D] Amphoteric.

Explanation: Calcium phosphate Ca3(PO4)2 is basic salt, as it is formed by the combination of a weak acid (phosphoric acid) and slightly stronger base (calcium hydroxide). Bacteria feed on sugars commonly found in foods and produce acids in the mouth decreasing the pH level to 5.5 or lower. Thus, eroding the enamel that is basic in nature.

One of the constituents of baking powder is sodium hydrogen carbonate, the other constituent is [A] Hydrochloric acid [B] Tartaric acid [C] Acetic acid [D] Sulphuric acid

Explanation: Baking powder is a mixture of baking soda NaHCO3 (sodium hydrogen carbonate) and a mild edible acid such as tartaric acid. When baking powder is mixed with water, sodium hydrogen carbonate reacts with tartaric acid and accepts hydrogen ions from it. This process releases carbon dioxide gas which is trapped in the dough when baking powder is used to make bread and cake.

To protect tooth decay we are advised to brush our teeth regularly. The nature of toothpaste commonly used is [A] Acidic [B] Neutral [C] Basic [D] Corrosive

Explanation: Toothpastes we generally contain mild bases such as sodium fluoride or sodium bicarbonate in their composition. The base reacts with the acid formed during tooth decay and neutralises its bad effects thus, preventing tooth decay.
Note: When we eat food containing sugar, then the bacteria present in our mouth break down the sugar to form acids (such as lactic acid). Thus, acid is formed in the mouth after a sugary food has been eaten. This acid lowers the pH in the mouth (making it acidic). Tooth decay starts when the pH of acid formed in the mouth falls below 5.5.

Which of the following substances will not give carbon dioxide on treatment with dilute acid? [A] Marble [B] Limestone [C] Baking soda [D] Lime

Explanation: Lime (CaO) is the base that reacts with a dilute acid such as HCl to form a salt called “Calcium Chloride”. It is an exothermic reaction and releases water but no carbon dioxide. Mable or limestone (CaCO3) or baking soda (NaHCO3) react with HCl to release CO2.