Solutions of Acids, Bases and Salts (Page No - 81) - Chemistry Lakhmir Singh, Class 10 | Extra Documents, Videos & Tests for Class 10 PDF Download

Question 38:
(a) What happens when zinc granules are heated with sodium hydroxide solution ? Write equation of the
reaction which takes place.
(b) What happens when bases react with non-metal oxides ? Explain with the help of an example. What does this reaction tell us about the nature of non-metal oxides ?
Solution :
(a) When zinc granules are heated with sodium hydroxide solution, then sodium zincate salt and hydrogen gas are formed.

(b) When bases react with non-metal oxides, then salt and water are formed. 

Example: Calcium hydroxide reacts with carbon dioxide to form calcium carbonate and water. 

Question 39:
(a) What effect does the concentration of H⁺ (aq) ions have on the nature of a solution ?
(b) What effect does the concentration of H^– ions have on the nature of a solution ?
(c) Someone put some universal indicator paper into vinegar. The pH is 3. What does this tell you about the vinegar ?
(d) Someone put some universal indicator paper onto wet soap. The pH is 8. What does this tell you about the soap ?
(e) State whether a solution is acidic, alkaline or neutral if its pH is :
(i) 9 (ii) 4 (iii) 7 (iv) 1 (v) 10 (vi) 3
Solution :
(a) As the concentration of hydrogen ions increases, the solution becomes more acidic.
(b) As the concentration of hydroxide ions increases, the solution becomes more basic.
(c) Vinegar is acidic in nature.
(d) Soap is basic in nature.
(e) ( i ) pH = 9 : Alkaline.
(ii) pH = 4 : Acidic.
(iii) pH = 7 : Neutral.
(iv) pH = 1 : Acidic.
(v) pH = 10 : Alkaline.
(vi) pH = 3 : Acidic.