WBBSE Class 9 Physical Science MCQ Questions Chapter 4.4 Acids, Bases and Salts

Well structured WBBSE Class 9 Physical Science MCQ Questions Chapter 4.4 Acids, Bases and Salts can serve as a valuable review tool before exams.

Acids, Bases and Salts Class 9 WBBSE MCQ Questions

Multiple Choice Questions :

Question 1.
Which element is present in all acids ?
(i) Hydrogen
(ii) Oxygen
(iii) Carbon
(iv) Nitrogen
Answer:
Hydrogen

Question 2.
ZnO is –
(i) acidic
(ii) basic
(iii) amphoteric
(iv) neutral oxide
Answer:
amphoteric

Question 3.
The weak acid is
(i) HCl
(ii) HNO₃
(iii) H₂ SO₄
(iv) H₂ CO₃
Answer:
H₂ CO₃

Question 4.
Aqueous solution of P₂ O₅ is
(i) HPO₃
(ii) H₃ PO₄
(iii) H₃ PO₃
(iv) H₃ PO₂
Answer:
H₃ PO₄

Question 5.
Methyl orange is a/an ___
(i) base
(ii) alkali
(iii) indicator
(iv) oxide
Answer:
indicator

Question 6.
Minimum quantity of an indicator used in neutralisation reaction is ____
(i) 5 mL
(ii) 5.2 mL
(iii) 5.5 mL
(iv) 2-3 drops
Answer:
2-3 drops

Question 7.
The aqueous solution of bases turn red litmus into ____
(i) blue
(ii) colourtess
(iii) violet
(iv) yellow
Answer:
blue

Question 8.
NaCl is a/an ____
(i) normal
(ii) acid
(iii) basic
(iv) complex salt
Answer:
normal

Question 9.
The strong acid is _____
(i) H₂ SO₄
(ii) H₂ CO₃
(iii) H₃ PO₄
(iv) CH₃ COOH
Answer:
H₂ SO₄

Question 10.
Caustic soda is a/an _______
(i) salt
(ii) weak base
(iii) strong base
(iv) acid
Answer:
strong base

Question 11.
Sulphuric acid is a/an _________
(i) inorganic acid
(ii) organic acid
(iii) weak acid
(iv) hydracid
Answer:
inorganic acid

Question 12.
Disodium hydrogen phosphate is a/an ______
(i) normal salt
(ii) basic salt
(iii) acid salt
(iv) double salt
Ans.
acid salt

Question 13.
Which of the following compounds is used to prepare vanishing colour
(i) NH₄ OH
(ii) NaOH
(iii) Ca(OH)₂
(iv) KOH
Answer:
NH₄ OH

Question 14.
Na₂ SO₄ is a/an ____
(i) normal salt
(ii) acid sait
(iii) basic salt
(iv) complex salt
Answer:
normal salt

Question 15.
Indicator used for neutralisation reaction of H₂ SO₄ and NaOH is _____
(i) methyl orange
(ii) phenolphthalein
(iii) litmus
(iv) any indicator
Answer: any indicator

Question 16.
The colour of phenolphthalein in dilute sulphuric acid solution becomes –
(i) red
(ii) yellow
(iii) blue
(iv) colourless
Answer:
colourless

Question 17.
The colour of methyl orange in acidic solution becomes –
(i) red
(ii) yellow
(iii) blue
(iv) orange
Answer:
red

Question 18.
Sulphuric acid contains
(i) 1
(ii) 2
(iii) 3
(iv) 4 replaceable hydrogen atom/atoms by a metal.
Answer:
2

Question 19.
Ammonia is
(i) an acid
(ii) a base
(iii) a salt
(iv) none of these
Answer:
a base

Question 20.
The acidity of CaO is ___
(i) 1
(ii) 2
(iii) 3
(iv) 4
Answer:
2

Question 21.
The basicity of hydrochloric acid is
(i) 1
(ii) 2
(iii) 3
(iv) 4
Answer:
1

Question 22.
Phosphoric acid is a –
(i) monobasic acid
(ii) dibasic acid
(iii) tribasic acid
(iv) none of these
Answer:
tribasic acid

Question 23.
An aqueous solution turns blue litmus solution into red. Excess addition of which of the following solution to the above solution reverse the change –
(i) HCl solution
(ii) vinegar solution
(iii) H₂ SO₄ solution
(iv) caustic soda solution
Answer:
caustic soda solution

Question 24.
Which of the following substance change the colour of pH paper to greenish – blue ?
(i) common salt
(ii) vinegar
(iii) an antacid
(iv) orange juice
Answer:
An antacid

Question 25.
To protect tooth decay you are advised to brush your teeth regularly, the nature of commonly used paste is –
(i) neutral
(ii) acidic
(iii) basic
(iv) corrosive
Answer:
Basic

Question 26.
If you soak a pH paper into gastric juices, it will indicate a pH value of –
(i) more than 7
(ii) less thati 7
(iii) equal to 7
(iv) less than 1
Answer:
less than 7

Question 27.
Which of the following is responsible for acid rain ?
(i) N₂
(ii) CH₄
(iii) SO₂ and NO₂
(iv) H₂
Answer:
SO₂ and NO₂

Fill in the blanks :

1. An acidic oxide is called _______ of the acid, which forms with water.
Answer:
anhydride

2. An oxide is a ______ of oxygen formed with another element.
Answer:
compound

3. ______ oxides are some metallic oxides which behave both as an acidic and a basic oxide.
Answer:
Amphoteric

4. CO, NO are examples of _____ oxide.
Answer:
neutral

5. Basic oxides which are soluble in water produce _____ when they are disssolved in water.
Answer:
alkalis

6. A base in general is an oxide or hydroxide of a ____ and when reacts with an acid produces _____ and water.
Answer:
Metal, salt

7. _____ is a process in which acids and alkalis in equivalent quantities react in their aqueous solutions to produce salt and water.
Answer:
Neutralisation

8. An acid salt is produced when insufficient quantity of a base reacts with a ______ acid.
Answer:
polybasic

9. Normal salts are formed by the complete replacement of the replaceable ______ atoms from an acid molecule by a suitable substance.
Answer:
hydrogen

10. Indicators are some weak organic acids or bases which indicate distinctive _____ in acid, alkali and neutral solutions.
Answer:
colours

11. Substances with a pH value below 7 are _____
Answer:
acidic

12. The aqueous solution of a base makes _____ litmus blue.
Answer:
red

13. The colour of methyl orange in acid medium is _____ and that in alkaline medium is –
Answer:
Pinkish-red, Yellow

14. An aqueous solution of an acid turns ______ litmus into red.
Answer:
blue

15. pH scale is a scale that runs from ____ to _____.
Answer:
0, 14

16. Na₃ PO₄ is a _____ salt.
Answer:
normal

17. The substance used to determine the end point of neutralisation of an acid and a base is called _____.
Answer:
indicator

18. Al₂ O₃ is an _____ oxide.
Answer:
amphoteric

19. H₂ O is a ______ oxide.
Answer:
neutral

20. Pb(OH) NO₃ is a ______ salt.
Answer:
basic

21. HCN is hydracid but H₂ SO₃ is _____.
Answer:
oxyacid

22. Concentrated _______ is a strong oxidising acid.
Answer:
H₂ SO₄

23. An aqueous solution of acid must contain _____ ion.
Answer:
H⁺

24. The formula of permanganic acid is _____.
Answer:
HMnO₄

25. P₂ O₅ is an _____ oxide.
Answer:
acidic

26. Na₂ HPO₄ is an_____ salt.
Answer:
acid

27. K₄ [Fe(CN)₆] is a _____ salt.
Answer:
complex

28. Acetic acid is known as _____.
Answer:
Vinegar

29. Acids have a ______ taste.
Answer:
sour

30. Tooth enamel is made of ____.
Answer:
Ca₃ (PO₄)₂

31. pH value of pure water is ______.
Answer:
0

32. Exact pH value of acid rain is _____.
Answer:
5.6

33. ______ indicator is a such indicator which can determine the strength of solution.
Answer:
universal