Exploring Substances Acidic Basic and Neutral Class 7 Extra Questions and Answers Science Chapter 2

By tackling these Class 7 Science Extra Questions and Class 7 Curiosity Chapter 2 Extra Question Answer Exploring Substances Acidic Basic and Neutral, students will build a solid foundation in the topic.

Class 7 Science Chapter 2 Exploring Substances Acidic Basic and Neutral Extra Questions

Class 7 Science Chapter 2 Extra Questions on Exploring Substances Acidic Basic and Neutral

Exploring Substances Acidic Basic and Neutral Class 7 Very Short Question Answer

Question 1.
Which colour is given by blue litmus in acidic solution?
Answer:
Red

Question 2.
Which acid is found in lemon juice?
Answer:
Citric acid

Question 3.
What is the nature of baking soda?
Answer:
Basic

Question 4.
What is the colour of red rose extract in basic solution?
Answer:
Green

Question 5.
What is the colour of turmeric in basic solution?
Answer:
Red

Question 6.
How the neutral liquid affects litmus?
Answer:
No impact

Question 7.
Which acid is injected when red ant bites?
Answer:
Formic acid

Question 8.
What is added in soil to reduce acidity?
Answer:
Lime

Question 9.
In hydrangea, which colour flowers arc produced in acidic soil?
Answer:
Blue

Question 10.
Turmeric plant belongs to which family?
Answer:
Ginger family

Question 11.
What is formed in neutralisation?
Answer:
Salt, water and heat

Question 12.
What is the taste-characteristic of the substance which changes blue litmus in red?
Answer:
Sour

Question 13.
How the soap solution tastes?
Answer:
Bitter

Question 14.
What does it feel to touch the bases?
Answer:
Slippery

Question 15.
What is added to neutralise the acidic factory waste?
Answer:
Base

Exploring Substances Acidic Basic and Neutral Class 7 Short Question Answer

Question 1.
How acids and bases are identified with litmus paper?
Answer:
Blue litmus turned red in acids and red litmus turned blue in bases. Neutral liquid does not have any effect on litmus.

Question 2.
How is red rose extract used as an indicator?
Answer:
Red rose extract give red colour in acidic solution and green colour in basic solution, so it is used as an acid-base indicator.

Question 3.
How turmeric paper reacts in basic medium?
Answer:
In basic medium turmeric paper turned red from yellow, while in acidic and neutral medium it docs not have any effect.

Question 4.
What is the taste of acidic substances? Give examples.
Answer:
Acidic substances are sour in taste, e.g. lemon juice, vinegar, tamarind water etc. they all have acids.

Question 5.
Why baking soda is applied on ant bites? Answer: Ant bite injects formic acid in skin. Due to basic nature baking soda neutralises acid and relieves pain.

Question 6.
Which products are formed in neutrali¬sation reaction?
Answer:
Neutralisation is a reaction between acid and base which makes the solution neutral and form salt, water and heat.

Question 7.
How the acidity of soil is reduced?
Answer:
Acidic soil is treated with lime (calcium hydroxide), which neutralises the soil and make it neutral or basic.

Question 8.
How does colour of hydrangea flower depends on acidic or basic nature of soil?
Answer:
Hydrangea plants produce blue flower in acidic soil and pink or red flower in basic soil.

Exploring Substances Acidic Basic and Neutral Class 7 Long Question Answer

Question 1.
Explain natural indicators with two examples.
Answer:
Natural indicators are obtained from nature, not by any chemical reaction.
Ex. 1. Red rose extract: Give red colour in acidic medium and green colour in basic/alkaline medium.
Ex. 2. Turmeric paper: Turns into red colour in basic medium and does not show any colour change in acidic medium.

Question 2.
How does acidic, basic and neutral solutions are identified?
Answer:
These are identified with litmus paper, natural indicator or pH paper. Acid changes blue litmus into red, and bases change red litmus into blue, and litmus does not change colour in neutral solution.

Question 3.
Why does turmeric not used to identify acids?
Answer:
Turmeric paper only changes colour in basic medium, it does not change colour in both acids and neutral substances, so it is not used in identification of acids.

Question 4.
How ant bite is treated by neutralisation?
Answer:
An ant bite injects formic acid in skin. So to neutralise it basic baking soda is applied, which helps to relieve pain.

Question 5.
What is done to neutralise acidic soil?
Answer:
Acidic soil is treated with lime, which is a base to neutralise it. It is essential for better growth of plants in agriculture.

Question 6.
What is the role of neutralisation to treat acidic industrial wastes?
Answer:
Acidic industrial wastes are treated with bases before releasing into water, which helps to save aquatic organism and reducing pollution.

Question 7.
Explain identification of acid and base by natural indicator.
Answer:
Natural indicators are substances which shows different colours in acidic and basic solutions, ex. turmeric paper turns red from yellow in basic medium, whereas it does not change colour in acidic medium. These are easily obtained from plants and provide a safe option for chemical experiments.

Question 8.
Write the importance of neutralisation with example.
Answer:
Neutralisation is a chemical reaction in which acid and bases form salt, water and heat by reacting with each other. It is important in medical, agriculture and industry, e.g. ant bite injects formic acid in skin which is neutralises by applying baking soda. In agriculture, acidic soil is neutralised by mixing lime, which is a base. This reaction provide easy solutions for many daily life problems.

Question 9.
Write impact of acidity and basicity of soil on plants and also tell how to fix it.
Answer:
Acidity and basicity of soil have a deep impact on plant growth. In acidic soil, roots of plant could not absorb nutrients properly and in basic medium, availability of nutrients is reduced. In acidic soil, lime is mixed to make it basic or neutral and organic manure or compost is mixed in basic soil to neutralise it. To maintain adequate acidity or basicity is essential for a good crop production.

Question 10.
Explain the role of neutralisation in treatment of industrial waste.
Answer:
Some industries release acidic waste in water, which is harmful for aquatic organisms lives in rivers and lakes. Before releasing these wastes into water, basic substances (lime, sodium hydroxide) are mixed to neutralise. This process is known as neutralisation. It is important to reduce water pollution and to save environment. It also become useful after proper treatment which helps to save resources.