TS 7th Class Science Important Questions 2nd Lesson Acids and Bases

These TS 7th Class Science Important Questions 2nd Lesson Acids and Bases will help the students to improve their time and approach.

TS 7th Class Science Important Questions 2nd Lesson Acids and Bases

Question 1.
What are indicators, give examples.
Answer:
The substances which can change colour when added to other substances are called indicators.
Eg : Red litmus, blue litmus paper, methyl orange etc.

Question 2.
Write the differences between natural and laboratory reagents
Answer:

Natural reagents	Laboratory reagents
1. The reagents made from plants are called natural reagents. 2. Eg : Turmeric, rose paper	1. The reagents made from chemicals are called laboratory reagents. 2. Eg: Methyl orange, phenopthalein

Question 3.
Write the differences between acids and bases.
Answer:

Acids	Bases
1. The substances that turn blue litmus into red are called acids.	1. The substances that turn red litmus into blue are called bases.
2. Acids turn colour of methyl orange indicator into red.	2. Bases turn colour of methyl orange indicator into yellow.
3. Acids do not change the colour less of phenolpthalin indicator.	3. Bases turn colourless phenolphthale in indicator into pink colour.
4. Eg: Hydrochloric acid, sulphuric acid	4. Eg: Sodium hydroxide, magnesium hydroxide.
5. Acids are sour to taste.	5. Bases are bitter to taste.

Question 4.
What is neutralization? Give example.
Answer:
When acids and bases are mixed in difinite proportions, they give neutral solution. This process is called neutralization.
Eg: By neutralizing Hydrochloric acid solution with Sodium hydroxide solution a salt (Sodium chloride) and water are formed.

Question 5.
Give examples of natural acids and mineral acids.
Answer:
Natural acids: Formic acid, Citric acid, Malic acid.
Mineral acids: Hydrochloric acid, Sulphuric acid, Nitric acid.

Question 6.
What happens when Hydrochloric acid reacts with Zinc pieces?
Answer:
Hydrogen gas is liberated.

Question 7.
What happens when Sulphuric acid reacts with pieces of marbles?
Answer:
Carbondioxide gas is liberated.

Question 8.
How can you identify bases by touch?
Answer:
Bases are soapy to touch.

Question 9.
What are acidic salts ? Give examples.
Answer:
Salts which show acidic nature are called acidic salts. Eg: NH₄Cl, CuSO₄

Question 10.
What are basic salts ? Give examples.
Answer:
Salts which show basic nature are called basic salts. Eg : CH₃COONa, Na₂S

Question 11.
What are neutral salts ? Give examples.
Answer:
Salts which show neutral nature are called neutral salts. Eg : Sugar, Glucose,Salt (Nacl)

Question 12.
What are acid rains?
Answer:
Acids like Carbonic acid, Sulphuric acid and Nitric acid when dissolves in rain water is called acid rain.

Question 13.
How are acid rains formed?
Answer:
Industrial waste gases containing Sulphur dioxide, Nitrogen oxide, Carbon dioxide when they get mixed with moisture they change to acid rains.

Question 14.
What are effects of acid rains?
Answer:
Acid rains cause damage to buildings and monuments, They reduce fertility of soils and also damage to our skin.

Question 15.
If soil becomes acidity, why lime is added to the soil?
Answer:
Lime water contains Calcium hydroxide, which is a base. It neutralizes the acidity of the soil.

Question 16.
For acidity problem, why doctors prescribe antacid drugs.
Answer:
Antacid drugs contain bases like Magnesium hydroxide, Aluminium hydroxide which neutralizes the acidity in our stomach.

Question 17.
Why are pickles, jams, jellies preserved in glass, porcelein and plastic containers.
Answer:
Pickles, jams, jellies contain acetic acid, if these are preserved in metal containers for a long time, then metals react with acids present in the materials and damages. To avoid this, pickles are preserved in glass, porcelein containers.

Question 18.
What questions you would pose to know about nature and uses of Acids and Bases?
Answer:

• Why do we know the sabstance whether it is acid or base?
• What are the advantages we get after knowing acids and bases?
• How do we use acids in our day to day life?
• How do we use bases in our day to day life.

Question 19.
In our daily life we come across many occasions of using of acids, bases and salts : Mention the occasions.
Answer:
Uses of common acids

• Vinegar is used in biryani or palav.
• Aspirin is used as medicine.
• Carbonic acid is used in cool drinks.
• Hydrochloric acid is released in our stomach to kill bacteria.
• Sulphuric acid is used in batteries.
• Nitric acid is used as fertilizer.

Uses of Common bases:

• Aluminium hydroxide is used as deodorant.
• Ammonium hydroxide is used as glass cleaner.
• Baking soda is used in food material.
• Sodium carbonate is used as dish detergent.

Uses of salts :

• Salt plays an important role in our daily life.
• We use soaps for bathing. Soaps contain salts.
• Sodium chloride is common salt used in our food material.

Question 20.
What did you observe while applying soap on the body? What type of chemicals are in the soap ? Acids or bases?
Answer:
Soap was slipped from the hands. Soap contains bases. Bases are slippery to touch in nature.

Question 21.
Suppose you tested lemon juice and magnesium mixture with burning stick. What would be the results?
Answer:
Keeping burning match stick on the the lemon and zinc mixture a tup sound occurs creating tup sound leads producing some gas called Hydrogen.

Question 22.
Write the information about chemicals that are used by farmers?
Answer:
Farmers use calcium hydroxide in order to reduce acidic condition of crop fields. Some basic natured flertilizers also pollute the crop field. In order to reduce the basic condition farmers use acidic based chemicals.

Question 23.
Present the written form about the cities which are affected with acids?
Answer:
CO₂, Sulphurdioxide, Nitic oxide etc emitted from wastes react with atmospheric humidity and convert into sulphuric acid, Nitric acid, carbonic acids. These acids melt in rain water and fall as acid rains.

Question 24.
Read the table and answer the questions.

Name of the base	Use
1. Ammonium hydroxide 2. Sodium hydroxide 3. Calcium hydroxide 4. Aluminium hydroxide	for removal of greeze stains manufacturing of soaps Bleaching powder industry Used as fire extinguishers

i. If you want to prepare fire extinguisher what substance is used?
Answer: Aluminium hydroxide

ii. People depend on sodium hydroxide for preparation what products?
Answer: Soaps

iii. Kranthi’s dress is unexpectedly stained with greeze. Then what chemical is used by him?
Answer: Ammonium hydroxide.

iv. To make water disinfectant what is to be used ?
Answer:
Calcium hydroxide is used in bleaching powder. Recently it was found that affect acid rains in Visakhapatnam and pathancheru in Hyderabad. Only because of over industrialisation occured in those cities.

Question 25.
What is the acid in the experiment. Find out the product that is relieved from egg husk and lemon juice ? Write the observation occurs in lime water.
Answer:
In the given experiment lemon juice is the acid. When it reacts with egg substance it releases the gas called carbondioxide. Carbondioxide turns the lime water into milky substance.

Choose the correct answer :

I. Conceptual Understanding

Question 1.
Acids are to taste. ( )
A) Bitter
B) Sour
C) Sweet
D) Spicy
Answer:
B) Sour

Question 2.
An example of natural acid ( )
A) Hydrochloric acid
B) Sulphuric acid
C) Formic acid
D) Nitric acid
Answer:
C) Formic acid

Question 3.
The colour of Methyl orange indicator in acidic solution ……………… ( )
A) Blue
B) Red
C) Yellow
D) Pink
Answer:
B) Red

Question 4.
The colour of Methyl orange indicator in basic solution …. ( )
A) Blue
B) Red
C) Yellow
D) Pink
Answer:
C) Yellow

Question 5.
The colour of Phenophthalein indicator in basic solution ( )
A) Red
B) Blue
C) Pink
D) Orange
Answer:
C) Pink

Question 6.
In the following, which one is neutral solution ( )
A) Vinegar
B) Tea
C) Lime water
D) Sugar
Answer:
A) Vinegar

Question 7.
When acids react with metals gas is evolved ( )
A) Hydrogen
B) Oxygen
C) Carbon dioxide
D) Nitrogen
Answer:
A) Hydrogen

Question 8.
An example of natural indicator. ( )
A) Methyl orange
B) Phenolphthalein
C) Turmeric paper
D) Litmus paper
Answer:
C) Turmeric paper

Question 9.
For removing ink stains on clothes acid is used ( )
A) Sulphuric acid
B) Oxalic acid
C) Hydrochloric acid
D) Acetic acid
Answer:
D) Acetic acid

Question 10.
Oxides of Magnesium dissolved in water forms ( )
A) Acidic
B) Basic
C) Neutral
D) None
Answer:
B) Basic

II. Asking Questions and Making Hypothesis

Question 11.
When a scratch is contacted with lemon juice we feel burning sensation. Why? ( )
A) acidic condition of lemon juice
B) basic condition of lemon juice
C) salinity of lemon juice
D) B or C
Answer:
A) acidic condition of lemon juice

Question 12.
Why farmers use calcium hydroxide in the field? ( )
A) to reduce acidic condition
B) to reduce basic condition
C) to reduce salts
D) to increase salinity
Answer:
A) to reduce acidic condition

Question 13.
One of the following is odd one. Find out? ( )
A) Acetic acid
B) Lactic acid
C) Lime water
D) Sulphuric acid
Answer:
C) Lime water

Question 14.
Which product does not belong to base. ( )
A) soaps
B) palm oil
C) glass cleaner
D) lime water
Answer:
B) palm oil

III. Experimentation and Field Investigation

Question 15.
Acids turn due to addition of methyl orange. ( )
A) yellow
B) blue
C) green
D) red
Answer:
D) red

Question 16.
10 drops of dilute hydrochloric acid is mixed with 2 drops of phenolptholene solution followed by sufficient adding of baking soda. What would be the result? ( )
A) basic solution is formed
B) acidic solution is formed
C) neutral solution is formed
D) no change
Answer:
A) basic solution is formed

Question 17.
You conducted tests on butter milk, tomato, grape juice etc., what type of conditions are seen in those substances? ( )
A) Base
B) salts
C) acid
D) no condition at all
Answer:
C) acid

Question 18.
You found that the eating food is sour in taste ? What type of substance it is? ( )
A) Salt
B) acid
C) base
D) acid and base
Answer:
B) acid

Question 19.
Ram felt burning sensation at the site of ant bite. What is the reason behind? ( )
A) ant secretes formic acid
B) ant secretes nitric acid
C) ant secretes sodium cabonate
D) ant secretes salt
Answer:
A) ant secretes formic acid

Question 20.
Testing copper pieces with lemon juice gives the result of producing. ( )
A) oxygen
B) carbondioxide
C) hydrogen
D) helium
Answer:
C) hydrogen

Question 21.
Suppose you tested hydrochloric acid with sodium bicarbonate. What would be the resultant product? ( )
A) Sodium acid
B) Hydrogen acid
C) Malic acid
D) Sodium chloride
Answer:
D) Sodium chloride

IV. Information Skills and Project

Question 22.
This is used in pickle industry ( )
A) citric acid
B) acetic acid
C) carbonic acid
D) oxalic acid
Answer:
B) acetic acid

Question 23.
Municipality and panchayat staff are using bleaching powder containing the base called ( )
A) Calcium hydroxide
B) Alluminium hydroxide
C) Sodium hydroxide
D) Potassium hydroxide
Answer:
A) Calcium hydroxide

Question 24.
Everyday people add this chemical in the foods without forgetting. ( )
A) oils
B) citric acid
C) malic acid
D) sodium chloride
Answer:
D) sodium chloride

Question 25.
Acid rains are more prominent in ( )
A) Industrialised areas
B) Forest regions
C) Residential areas
D) Desert regions
Answer:
A) Industrialised areas

Question 26.
Preserving pickles, jams, Jellies etc., are done only in China marble containers. Why? ( )
A) marble can’t form acids
B) marble react with pickles
C) marbles can’t react with food
D) A or C
Answer:
C) marbles can’t react with food

V. Communication through Drawing and Model Making

Question 27.
Observe the diagram. What gas is released from the reaction? ( )
A) oxygen
B) hydrogen
C) calcium
D) nitrogen
Answer:
B) hydrogen

VII. Appreciation and Aesthetic Sense and Values

Question 28.
If you want to cook a food with citric acid, what type of delicious item you would prepare?
A) Pulihora
B) Palav
C) Biryani
D) Chicken
Answer:
A) Pulihora

VIII. Application to Daily Life and Concern to Bio Diversity

Question 29.
Baking industry commonly depends on this chemical
A) Carbonic acid
B) Sodium bicarbonate
C) Potassium hydroxide
D) Malic acid
Answer:
B) Sodium bicarbonate

Question 30.
The chemical used in manufacturing of fertilizers and batteries.
A) Hydrochloric acid
B) Carbonic acid
C) Acetic acid
D) Sulphuric acid
Answer:
D) Sulphuric acid

Question 31.
We use sodium chloride in the name of …. in our day-to-day life.
A) baking soda
B) common salt
C) formic acid
D) citric acid
Answer:
B) common salt

Question 32.
Rub the turmeric paste on a white paper and sprinkle soap water it, then the colour appears ( )
A) Black
B) Red
C) Blue
D) Green
Answer:
B) Red

Question 33.
Choose the correct statement. (   )
A) Methyl orange gives blue colour with acids.
B) Methyl orange gives red colour with acids.
C) Methyl orange remains colourless with acids.
D) All of these
Answer:
B) Methyl orange gives red colour with acids.

Question 34.
Choose the correct statement.
A) Methyl orange gives yellow colour with base.
B) Methyl orange gives red colour with base.
C) Methyl orange gives red colour with acid.
D) Both A and C
Answer:
D) Both A and C

Question 35.
Choose the correct statement.
A) phenolphthalein remains colour in basic solution.
B) phenolphthalein remains colour in acidic solution.
C) phenolphthalein changes to blue colour in acids.
D) phenolphthalein changes to blue colour in bases.
Answer:
B) phenolphthalein remains colour in acidic solution.