Vidaara.orgClass 7 · Mathematics
CodeVID-M7-WS
Acids, Bases and Salts — Practice Worksheet
Name: ____________________
Roll No.: __________
Date: ____________
General Instructions
- All questions are compulsory.
- Choose the correct option (A, B, C or D) for each question.
- The answer key is at the end — try the paper first!
Section A — Multiple Choice (1 mark each)
25 × 1 = 25 marks
1.
Acids generally taste:
- A.Bitter
- B.Sour
- C.Salty
- D.Sweet
2.
An acid turns litmus paper which colour?
- A.Blue litmus red
- B.Red litmus blue
- C.Red litmus green
- D.Blue litmus yellow
3.
The acid present in vinegar is:
- A.Citric acid
- B.Acetic acid
- C.Lactic acid
- D.Tartaric acid
4.
Which of these is a strong mineral acid?
- A.Citric acid
- B.Lactic acid
- C.Sulphuric acid
- D.Tartaric acid
5.
The acid produced in the human stomach to help digestion is:
- A.Nitric acid
- B.Hydrochloric acid
- C.Acetic acid
- D.Citric acid
6.
Bases generally taste:
- A.Sour
- B.Bitter
- C.Salty
- D.Sweet
7.
A base turns litmus paper which colour?
- A.Blue litmus red
- B.Red litmus blue
- C.Red litmus green
- D.Blue litmus yellow
8.
A base that dissolves in water is called a/an:
- A.Acid
- B.Salt
- C.Alkali
- D.Indicator
9.
Which substance is used in many antacids to relieve stomach acidity?
- A.Sulphuric acid
- B.Magnesium hydroxide
- C.Citric acid
- D.Sodium chloride
10.
Which of the following is a strong, corrosive base?
- A.Baking soda
- B.Lime water
- C.Sodium hydroxide
- D.Toothpaste
11.
A substance that changes colour to show if something is an acid or base is a/an:
- A.Salt
- B.Indicator
- C.Alkali
- D.Catalyst
12.
Litmus is a natural dye obtained from:
- A.Roses
- B.Lichens
- C.Turmeric
- D.Cabbage
13.
Phenolphthalein turns which colour in a basic solution?
- A.Colourless
- B.Pink
- C.Red
- D.Yellow
14.
Turmeric, a natural indicator, turns red in the presence of a:
- A.Acid
- B.Base
- C.Salt
- D.Neutral substance
15.
Methyl orange turns red in the presence of a/an:
- A.Base
- B.Acid
- C.Salt
- D.Alkali
16.
The pH scale runs over the range of values from:
- A.0 to 7
- B.0 to 14
- C.1 to 10
- D.7 to 14
17.
A solution with a pH of exactly 7 is:
- A.Strongly acidic
- B.Neutral
- C.Strongly basic
- D.Weakly basic
18.
A solution with a pH less than 7 is:
- A.Acidic
- B.Basic
- C.Neutral
- D.A salt
19.
As the pH value rises above 7, the solution becomes increasingly:
- A.Acidic
- B.Neutral
- C.Basic
- D.Sour
20.
Which solution is the strongest acid?
- A.pH 6
- B.pH 4
- C.pH 2
- D.pH 7
21.
The reaction between an acid and a base is called:
- A.Oxidation
- B.Neutralisation
- C.Crystallisation
- D.Corrosion
22.
The products formed in a neutralisation reaction are:
- A.Salt and hydrogen
- B.Salt and water
- C.Acid and base
- D.Water only
23.
Common table salt is chemically known as:
- A.Sodium hydroxide
- B.Sodium chloride
- C.Sodium sulphate
- D.Calcium carbonate
24.
An antacid relieves stomach acidity because it is a mild:
- A.Acid
- B.Base
- C.Salt
- D.Indicator
25.
Acid rain is formed when rainwater dissolves polluting gases such as:
- A.Oxygen and nitrogen
- B.Sulphur and nitrogen oxides
- C.Carbon and helium
- D.Water vapour only
Answer Key
Section A — Multiple Choice (1 mark each)
- (B) Sour
- (A) Blue litmus red
- (B) Acetic acid
- (C) Sulphuric acid
- (B) Hydrochloric acid
- (B) Bitter
- (B) Red litmus blue
- (C) Alkali
- (B) Magnesium hydroxide
- (C) Sodium hydroxide
- (B) Indicator
- (B) Lichens
- (B) Pink
- (B) Base
- (B) Acid
- (B) 0 to 14
- (B) Neutral
- (A) Acidic
- (C) Basic
- (C) pH 2
- (B) Neutralisation
- (B) Salt and water
- (B) Sodium chloride
- (B) Base
- (B) Sulphur and nitrogen oxides
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