In this page we have Class 10 Science Acid base and Salts Important questions . Hope you like them and do not forget to like , social shar
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a. One Marks Questions
b. Two Marks Questions
c. Fill in the blanks
d. True and False
e. 4 marks Questions
f. Long answer questions(5 Marks)
One Marks Questions
Question 1
What is a neutralization reaction ?
Answer
A reaction in which an acid and a base react to give a salt and water is known as a �neutralization reaction�. For example,
NaOH (aq) + HCl (aq) �> NaCl (aq) + H2O (liq)
Ca(OH)2 (aq) + H2SO4 (aq) �> CaSO4 (s) + H2O
Question 2
What will be the products of the following reaction?
HCI + NaOH
Answer
NaOH (aq) + HCl (aq) �> NaCl (aq) + H2O (liq)
Question 3
pH stands for the negative logarithm of the hydrogen ion concentration. True or false ?
Answer
True
Question 4
Name two indicators which are widely used in laboratories?
Answer
A few common indicators used in the laboratory are:
1. Litmus Paper
2. Methyl Orange
Question 5 What is brine?
Answer
Water solution containing more than 2.6 percent salt (the amount contained in sea water), used in the manufacture of caustic soda (sodium hydroxide), chlorine, sodium carbonate and other products. Used also in curing of hides, and pickling of meats and vegetables for canning.
Question 6 A solution turns red litmus blue. Is the solution acid or a base?
Answer
Basic
Question 7 What happens to the temperature of water when few drops of concentrated sulphuric acid is added to it?
Answer
temperature rises
Question 8 Which compound of sodium is used for softening of hard water?
Answer
Washing Soda (Na2CO3.10H2O) is hydrated sodium carbonate which is used for softening hard water.
Question 9 Does distilled water conduct electricity?
Answer
No
Question 10 What are olfactory indicators? Give an example. Question 11 What is the chemical formula for baking soda? Question 12 What is the organic acid present in tomato?
Two Marks Questions
Question 1
What are indicators?
Answer
Indicators are weak inorganic compounds which change color in accordance with the pH of the solution.
Indicators dissociate slightly in a solution producing - ions and dissociated molecules.The color of the ions produced is dependent on the - hydrogen ion concentration.
Question 2
What would happen if a small amount of copper oxide is taken in a beaker and dilute HCI is added to it? Question 3
What is the 'pH' of pure water and that of rain water? Elaborate it
Answer
pH VALUE OF pure water us 7 i.e it is neither acidic nor basic.
Normal rainwater has a pH of 5.6 (slightly acidic). This is because it is exposed to the carbon dioxide in the atmosphere. The carbon dioxide gets dissolved in the rainwater and forms carbonic acid (H{-2}CO{-3}).
Question 4
How does plaster of Paris reacts with water? Write down the chemical equation?
Answer
plaster of Paris reacts with water to form gypsum
CaSO4.(1/2)H2O + 1(1/2) H2O -> CaSO4.2H2O
Question 5
What is dilute? Why care must be taken while mixing concentrated nitric acid or sulphuric acid with water? Question 6
On which factors does the strength of an acid or a base depend? Explain. Question 7
Name the common acid-base indicators used in the laboratory with their color change?
Answer
Fill in the blanks:
Binary acid contain __________ atom.
Chemical formula of baking soda is _____________
An acid that contains more than one acidic hydrogen atom is called a ________ .
When an acid reacts with a metal, _______ gas is evolved and a corresponding ________ is formed.
When an acid reacts with a metal carbonate or metal hydrogencarbonate, it gives the corresponding salt, ________ gas and _________.
_________ is the fixed number of water molecules chemically attached to each formula unit of a salt in its crystalline form.
Phenolphthalein and methyl orange are_________indicators.
Anhydrous sodium carbonate is commonly known as _________ .
Soda acid fire extingunisher contains a solution of sodium hydrogen carbonate and ___.
All alkali are bases but all bases are ______ alkali.
Alkali reacts with ammonium salts to produce corresponding salt, water and evolve ____.
Common name of sodium chloride is ……………….
Reaction of acids with bases are …………….. reactions.
Acids show their properties in the presence of …………….
CH3COONa salt is ………… in nature.
Answer
Fill in the blanks
hydrogen
NaHCO3
polyprotic acid
hydrogen, salt
carbon dioxide, water
Water of crystallization
synthetic
soda ash
sulphuric acid
not
ammonia
caustic soda
neutralization
water
basic
TRUE/ FALSE Questions
The colour of methyl orange turns red in acidic solution.
Acidic nature of a substance is due to the formation of H+ (aq) ions in solution.
Mixing concentrated acids or bases with water is a highly endothemic process.
The colour of caustic soda turns the pink when phenolphthalein is added.
Hydrogen chloride gas turns the blue litmus red.
Sodium hydrogen carbonate is used in fire extinguisher.
Baking soda on strong heating gives sodium oxide and carbon dioxide.
Plaster of paris is obtained by heating gypsum at 373 K in a kiln.
When acids react with metal oxide, salt and water is formed.
Carbonic acid is a weak acid.
Answer
True/ False
True
True
False
True
False
True
False
True
True
True.
Four Marks Questions
Question 1
Explain the following by giving examples>
How metal oxides react with acids?
How non- metal oxides react with base?
Question 2
Explain the terms with examples?
Acid Salt
Normal Salt
Basic salt
Double salt
Mixed salt
Question 3
(a) Why does acidic solution conduct electricity?
(b) Can basic solution conduct electricity?
(c) Can separation of H+ ions in acids take place when HCI is added to a non- aqueous solution?
(d) While diluting an acid, why is it recommended that the acid should be added to water and not water to the acid?
Answer
Both acidic and basic solutions in water conduct electricity. Acids, when dissolved in water release the H+ and bases when dissolved in water release the OH- ions. These ions are charged species and so act as charge carriers. In other words the conductivity of these solutions is due to the movement of these ions.
The process of dissolving an acid or a base in water is a highly exothermic one. Care must be taken while mixing concentrated acid with water. The acid must always be added slowly to water with constant stirring. If water is added to a concentrated acid, the heat generated may cause the mixture to splash out and cause burns. The glass container may also break due to excessive local heating.
Five Marks Questions Question 1
(a)What is pH scale and what’s its range? How is it related to hydronium ion concentration?
(b)Explain any two roles played by pH levels of various chemicals in living organisms.
Answer
The term "pH" is defined as the negative logarithm of H+ ion concentration of a given solution; the concentration being expressed as moles per litre.
Mathematically pH = � log [H+] �pH� stands for: Power of hydrogen ion concentration, �p� for power and �H� for H+ ion concentration.
Some important benchmark values in the pH scale are: pH = 7 indicates neutral solutions e.g., aqueous solutions. pH > 7 to 14 indicates alkaline solutions and pH < 7 to 0 indicate acidic solutions.
Question 2
Plaster of Paris should be stored in a moisture-proof container. Explain why? Question 3
A compound ‘X’ is a constitute of baking powder. It is used as an antacid. When ‘X’ is heated it gives out a gas ‘Y’ which when passed through lime water turns it milky and a salt ‘Z’ is formed which is the main constituent of washing powder. Identify ‘X’, ‘Y’ and ‘Z’. Write balanced chemical equations for the reactions involved. Question 4
How is Plaster of Paris chemically different from gypsum? How can they be interconverted? Write two uses of Plaster of paris. Question 5
Write one point of difference between each of the following:
(a) A hydrated salt and an anhydrous salt.
(b) Washing soda and soda ash.
(c) Baking soda and baking powder. Question 6
On the basis of their pH values, how will you identify neutral, acidic and basic salt solution? How are these salts prepared? Question 7 Give two uses each of sodium hydroxide, hydrogen and chlorine.
Answer
Sodium hydroxide a)It is used for making soaps and detergents.
(a)It is used for making artificial textile fibres(rayon)
Chlorine:
(a)Chlorine is used to sterilize drinking water and in swimming pool since it is a disinfectant.
(b)It is used inthe production of bleaching powder and HCl.
Question 8
When this white powder is mixed with water a hard solid mass is obtained. Write balanced chemical equation for this change. Question 9
Write name of the compound:
(a) Used for softening hard water.
(b) Used as an antacid.
(c) Which is a component of washing soda.
(d) Which is used as an oxidizing agent in many chemical industries? Question 10
A gas X reacts with lime water and forms a compound Y which is used as a bleaching agent in chemical industry. Identify X and Y. Give the chemical equation of the reaction involved.
Summary
This Class 10 Science Acid base and Salts Important questions with answers is prepared keeping in mind the latest syllabus of CBSE . This has been designed in a way to improve the academic performance of the students. If you find mistakes , please do provide the feedback on the mail.
