Q. 2) What do you mean by the acids? What are main types of the acids?
Ans.
The substances which are sour in taste and turn the blue litmus into red are called acids. The substances producers hydrogen ions (H+) when mixed with water.
The acids are of two types
a) Natural acids or organic acids
b) Mineral acids or inorganic acids.
Q. 3) What is pH scale ? What is the value of acid, base and neutral substance?
Q. 4) What is the importance of the pH scale in daily life? What is the importance for plants, teeth, milk, digestion and water?
Q. 5) What do you mean by the antacids ? Give two general examples of antacids.
Q. 6) Write the name of the acids find in the following substances:
Apple, vinegar, tamarind (imli), Orange, lemon, raw mango, tomato, Spanish, Curd, sour milk, Ant's sting, natal's sting.
Q. 7) You have two solution A and B the pH of solution A is 6 and pH of solution B is 8. Which solution has more hydrogen ion concentration and more hydroxyl ion concentration?
Q. 8) What do you mean by the indicators? What are its main types? Explain with examples.
Q. 9) What is common salt? What is its chemical name and chemical formula? What are its main properties ? How it is is prepared?
Q. 10) What is sodium hydroxide? What is its chemical name and chemical formula? What are its main properties ? How it is is prepared?
Q. 11) What is bleaching powder? What is its chemical name and chemical formula? What are its main properties ? How it is is prepared?
Q. 12) What is baking soda? What is its chemical name and chemical formula? What are its main properties ? How it is is prepared?
Q. 13) What is washing soda? What is its chemical name and chemical formula? What are its main properties ? How it is is prepared?
Q. 14) What is plaster of Paris? What is its chemical name and chemical formula? What are its main properties ? How it is is prepared?
Q. 15) What do you mean by the concentration and diluteness of the acids? How can we change the concentration of acids ?
Q. 16) define the following with examples.
slake lime, sodium bicarbe, baking powder, water of crystallization, Efflorescence, neutralization reaction.
Q. 17) You have been provided with three test tubes. One of them contains distilled water and the other two contains an acidic solution and basic solution respectively. If you are given only red litmus paper, how will you identify the contents of each test tube ?
Q. 18) Why should curd and sour substances not be kept in the brass and copper vessels?
Q. 19) Why does an aqueous solution of an acid conduct electricity?
Q. 19) Why does distilled water not conduct electricity whereas rainwater does?
Q. 20) The liquid HCl gas change the colour of dry litmus paper but the dry HCl gas not change the colour of the dry litmus paper why?
Q. 21) While diluting an acid, why is it recommended that the acid should be added to water and not water to the acid?
Q. 21) Do basic solution also have hydrogen ion? If yes then why are these basics?
Ans. Yes, basic solution also has hydrogen ion however their concentration is less as compared to the concentration of the hydroxyl ion of the solution that makes the solution basic.
Q. 23) Five solutions A, B, C, D and E when tested with the universal indicators showed pH as 4, 1, 11, 7 and 9 respectively. Which solution is
a) neutral
b) strongly alkaline
c) strongly acidic
d) weakly acidic
Q. 24) Why does a milkman adds a very small amount of baking soda to fresh milk? Why does he shift the pH of the fresh milk from 6 to slightly alkaline? Why does this milk take a long time to set as curd.
Q. 25) What do you mean by the indigestion or acidity ? What is the special name of the substances which is used to treat the indigestion or acidity?
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