Science
Date
2
radical from the following
Sapopate acid and alkali
and write them with
their charge
@ Cason B CH ₂ COONH, © Mgela
@ CaCOH)2
KNOS
2
Answers
Active Science Solutions for Class 7 Science Chapter 7 Acids, Bases And Salts are provided here with simple step-by-step explanations. These solutions for Acids, Bases And Salts are extremely popular among Class 7 students for Science Acids, Bases And Salts Solutions come handy for quickly completing your homework and preparing for exams. All questions and answers from the Active Science Book of Class 7 Science Chapter 7 are provided here for you for free. You will also love the ad-free experience on Meritnation’s Active Science Solutions. All Active Science Solutions for class Class 7 Science are prepared by experts and are 100% accurate.
Page No 90:
Question 1:
Acids
(a) turn blue litmus red
(b) have a sour taste
(c) react with carbonates to give carbon dioxide
(d) all of the above
ANSWER:
(d) all of the above
Acids have all these three properties.
Page No 90:
Question 2:
Which of the following can be used to neutralise an acid?
(a) common salt
(b) calcium hydroxide
(c) vinegar
(d) water
ANSWER:
(b) calcium hydroxide
Because calcium hydroxide is a base. A base is used to neutralise an acid.
Page No 90:
Question 3:
When a substance X was added to turmeric, there was no colour change. What can you conclude from this?
(a) X is not a base.
(b) X is an acid.
(c) X is a salt.
(d) X is a base.
ANSWER:
(a) X is not a base
Turmeric turns to brick red colour when it reacts with a base, but does not change its colour when an acid or a salt is added to it.
Page No 90:
Question 4:
In which of the following cases will a gas be given off?
(a) Hydrochloric acid is added to sodium carbonate
(b) Sulphuric acid is added to sodium hydroxide
(c) Sulphuric acid is added to copper oxide
(d) Hydrochloric acid is added to zinc oxide
ANSWER:
(a) Hydrochloric acid is added to sodium carbonate
In this reaction, the products are sodium chloride and water and carbon dioxide gas is evolved.
Page No 91:
Question 5:
Which of the following is not a salt?
(a) calcium carbonate
(b) sodium hydroxide
(c) potassium nitrate
(d) zinc chloride
ANSWER:
(b) sodium hydroxide
Because it is a base, not a salt.
Page No 91:
Question 6:
Which property is not common to all inorganic acids?
(a) sour taste
(b) reacts with sodium bicarbonate to give carbon dioxide
(c) forms acid salts
(d) turns blue litmus red
ANSWER:
(c) forms acid salts
Carbonic acid is a weak inorganic acid and does not react with weak bases and thus does not form acid salts on reaction with them.
Page No 91:
Question 7:
Which of these oxides reacts with water to form sulphuric acid?
(a) SO2
(b) SO3
(c) CO
(d) CO2
ANSWER:
(b) SO3
Sulphur trioxide (SO3) reacts with water to form sulphuric acid.
SO3 (g) + H2O (l) → H2SO4 (aq)
Sulphur trioxide Water Sulphuric acid
Page No 91:
Question 8:
The table below shows the pH values of some chemicals.
Chemical pH
hydrochloric acid 2
ammonium hydroxide 10
sulphuric acid 1
acetic acid 5