Class 10 Science Chapter 2 Question Answers - Acids, Bases and Salts

Q1: The substances used to test whether a substance is acidic or basic are known as ________

Ans: The substances used to test whether a substance is acidic or basic are known as Indicators

Q2: Name the most commonly used indicator.

Ans: Litmus paper

Litmus Paper

Q3: Form where do we extract litmus to be used as an indicator?

Ans: Lichens

Q4: In acidic solution, litmus paper turns into ______

Ans: In acidic solution, litmus paper turns into Red
Litmus paper is a pH indicator that turns red in acidic solutions, indicating the presence of acids.

Q5: In basic solution, litmus paper turns into ____

Ans: In basic solution, litmus paper turns into Blue
Litmus paper changes to blue in basic solutions, indicating the presence of bases.

Q6: In distilled water, litmus paper turns into _________

Ans:  In distilled water, litmus paper turns into purple
Litmus paper remains purple in neutral distilled water, as it is neither acidic nor basic.

Q7: The reaction between an acid and a base is known as _________

Ans: The reaction between an acid and a base is known as neutralization.
Neutralization is the chemical reaction that occurs when an acid and a base react to form water and a salt.

Q8: China rose indicator turns acidic solutions _______

a. Dark pink

b. Purple

c. Blue

d. None of these

Ans: a. Dark pink
China rose indicator changes to dark pink in acidic solutions, indicating their acidic nature.

Q9: China rose indicator turns basic solutions to ______

a. Dark pink

b. Purple

c. Blue

d. Green

Ans: d. Green

• The China rose indicator changes the colour of basic solutions to green.
• In contrast, it turns acidic solutions to dark pink.

Q10: Salt and water are produced in the neutralization process with the evolution of ____________

Ans: Salt and water are produced in the neutralization process with the evolution of Heat

Q11: Name the acid present in our stomach.

Ans: HCL is present in our stomach.
Hydrochloric acid helps break down food and activates digestive enzymes, facilitating the digestion process.

Q12: What role does HCL present in our stomach play?

Ans: It helps in the digestion of food.

Q13: Name the acid present in the sting of an ant.

Ans: Formic acid is present in the sting of an ant.

Q14: State the nature of the soap solution.

Ans: Basic

Q15: State the nature of baking soda.

Ans: Basic

Q16: State the nature of lemon juice.

Ans: Acidic

Q17: Why does lemon juice and orange juice taste sour?

Ans: Because they contain acids.

Q18: Why does baking soda taste bitter?

Ans: Because it is basic in nature. 

Q19: State one property of acids.

Ans: Acids are sour in taste.

Q20: State one property of bases.

Ans: Bases are bitter in taste.

Q21: Tina rubs a solution between her fingers and feels soapy; what is the nature of that solution?

Ans: Basic

Q22: Complete the following reaction: 

H C l + N a O H ----> ______ + H₂O

Ans: NaCl

Q23: Ammonia is found in many household products, such as window cleaners. It turns red litmus blue. its nature _______________

Ans: Ammonia is found in many household products, such as window cleaners. It turns red litmus blue. its nature Basic

Q24: The wastes of many factories contain____________

Ans: The wastes of many factories contain Acids

Q25: Blue litmus paper is dipped in a solution. It remains blue, what is the nature of the solution?

Ans: Basic

Q26: Name the acid that is present in fats in our body.

Ans: Fatty acid

Q27: Each cell in our body contains an acid, name that acid.

Ans: the deoxyribonucleic acid

Q28: Hydrogen ion is common to all acids. True/False

Ans: True

Q29: Name a base that is also used in soda acid fire extinguishers.

Ans: Baking soda.

Q30: Which gas is liberated when an acid reacts with metals?

Ans: Hydrogen gas

Q31: The hydrogen ions combine with H₂O to form ____________

Ans: hydronium ions (H3O⁺)

Q32: Aqueous solution of acid conducts electricity due to ______________ present in it.

Ans:  ion

Q33: What is the common name of the compound CaOCl₂?

Ans: Bleaching powder

Q34: Name a universal indicator.

Ans: pH Scale

Q35: Define pH.

Ans: pH is the measure of the Acidity or Alkalinity of a solution. The term pH stands for a negative log of hydrogen ion concentration.

Q36: The bases that dissolve in water are known as alkalies. True/ False.

Ans: True

Q37: What is brine?

Ans: Aqueous solution of sodium chloride (NaCl) is known as brine.

Q38: Phenolphthalein becomes colourless in __________ and pink in_________.

Ans: Colourless in acid and pink in base.

Q39: What is the colour of methyl orange in an acidic solution?

Ans: Pink

Q40: Name the acid present in vinegar.

Ans: Acetic acid

Q41: Name the acid present in lemon.

Ans: citric acid

Q42: Nitric acid turns red litmus blue. True/ False.

Ans: False

Q43: Tooth decay is caused by the presence of bases. True/ False.

Ans: False

Q44: Change of colour in an acid or base depends on

a. Type of indicator

b. The acidic property of that substance

c. Basis property of that substance

d. None of these

Ans: Type of indicator

Q45: Name the acid present in curd.

Ans: Lactic acid