Class 10 Acid base and Salts Important questions-1
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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One Marks Questions
Question 1What is a neutralization reaction? Solution
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 2What will be the products of the following reaction?
HCI + NaOH Solution
NaOH (aq) + HCl (aq) �> NaCl (aq) + H2O (liq)
Question 3pH stands for the negative logarithm of the hydrogen ion concentration. True or false Solution
True
Question 4Name two indicators which are widely used in laboratories. Solution
A few common indicators used in the laboratory are:
1. Litmus Paper
2. Methyl Orange
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 6A solution turns red litmus blue. Is the solution acid or a base? Solution
Basic
Question 7What happens to the temperature of water when few drops of concentrated sulphuric acid is added to it? Solution
temperature rises
Question 8Which compound of sodium is used for softening of hard water? Solution
Washing Soda (Na2CO3.10H2O) is hydrated sodium carbonate which is used for softening hard water.
Question 9Does distilled water conduct electricity? Solution
No
Question 10What are olfactory indicators? Give an example. Question 11What is the chemical formula for baking soda Question 12What is the organic acid present in tomato?
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 2What would happen if a small amount of copper oxide is taken in a beaker and dilute HCI is added to it? Question 3What is the 'pH' of pure water and that of rain water? Elaborate it Solution
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 4How does plaster of Paris reacts with water? Write down the chemical equation? Solution
plaster of Paris reacts with water to form gypsum
CaSO4.(1/2)H2O + 1(1/2) H2O -> CaSO4.2H2O
Question 5What is dilute? Why care must be taken while mixing concentrated nitric acid or sulphuric acid with water? Question 6On which factors does the strength of an acid or a base depend? Explain. Question 7Name the common acid-base indicators used in the laboratory with their color change. Solution
Indicator
Final colour
Acid
Alkali
Litmus
Red
Blue
Methyl orange
Pink
Yellow
Phenolphthalein
Colour-less
Deep pink
Four Marks Questions
A) Explain the following by giving examples
How metal oxides react with acids?
How non- metal oxides react with base?
B) Explain the terms with examples
Acid Salt
Normal Salt
Basic salt
Double salt
Mixed salt
C)
1) Why does acidic solution conduct electricity?
2) Can basic solution conduct electricity?
3) Can separation of H+ ions in acids take place when HCI is added to a non- aqueous solution?
4) While diluting an acid, why is it recommended that the acid should be added to water and not water to the acid? Solution
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. Solution
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.
athematically 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?
