Very Short Question Answers: Acids, Bases & Salts Notes | Study Science Class 7 - Class 7

Very Short Q & A :

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

Ans : Indicators

Q2: Name the most commonly used indicator.

Ans : Litmus paper

Litmus Paper

Q3: Form where does we extract litmus to be used as indicator.

Ans : Lichens

Q4: In acidic solution, litmus paper turns into ------

Ans : Red

Q5: In basic solution, litmus paper turns into ------

Ans : Blue

Q6: In distilled water , litmus paper turns into _________

Ans : purple

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

Ans : The reaction between an acid and a base is known as neutralisation.

Q8: China rose indicator turns acidic solutions ------

1. Dark pink
2. Purple
3. Blue
4. None of these

Ans : Dark pink

Q9: China rose indicator turns basic solutions to ------

1. Dark pink
2. Purple
3. Blue
4. Green

Ans : Green

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

Ans : Heat

Q11: Name the acid present in our stomach.

Ans : HCL

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

Ans : It helps in digestion of food

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

Ans : Formic acid

Q14: State the nature of soap solution.

Ans : Basic

Q15: State the nature of baking soda.

Ans : Basic

Q16: State the nature of lemon juice.

Ans : Acidic

Q17: Why lemon juice and orange juice tastes sour?

Ans : Because they contain acids.

Q18: Why baking soda taste sour?

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 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 : Basic

Q24: The wastes of many factories contain____________

Ans : 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 conduct 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 Acidity or Alkalinity of a solution. The term pH stands for 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 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

1. Type of indicator
2. Acidic property of that substance
3. Basis property of that substance
4. None of these

Ans : Type of indicator

Q45: Name the acid present in curd.

Ans : Lactic acid