Unit 9 – Acid, Base and Salts Short Questions
Q.2 Define a base and explain all alkalies are bases, but all bases are not alkalies.
Q.3 Define Bronsted-Lowry base and explain with an example that water is a Bronsted
Lowry base.
Q.5 Which kind of a bond forms between a Lewis acid and a base?
Q.6 Why H+ ion acts as a Lewis acid?
Q.7 Name two acids used in the manufacture of fertilizers.
Q.8 Define pH. What is the pH of pure water?
Q.9 How many times a solution of pH=1 will be stronger than that of a solution having pH=2?
Q.10 Define the followings:
(i) Normal salt (ii) Basic salt
Q.11 Na2SO4 is a neutral salt while NaHSO4 is an acid salt. Justify.
Q.12 Give a few characteristic properties of salts.
Q.13 How the soluble salts are recovered from water?
Q.14 How the insoluble salts are prepared?
Q.15 Why á salt is neutral, explain with an example?
Q.16 Name an acid used in the preservation of food.
Q.17 Name the acids present in: (i) Vinegar (ii) Ant sting (iii) Citrus fruit (iv) Sour milk
Q.18 How can you justify that Pb(OH)NO3 is a basic salt?
Q.19 You are in a need of an acidic salt. How can you prepare it?
Q.20 Which salt is used to prepare plaster of Paris?
Q.1 Name three common household substances having
(a) pH value greater than 7
(b) pH value less than 7
(c) pH value equal 7
Answer:
(a) pH value greater than 7
(i) Calcium hydroxide Ca(OH)2
(ii) Potassium hydroxide KOH
(iii) Sodium hydroxide NaOH
(b) pH value less than
(i) Hydrochloric acid HCL
(ii) Nitric acid HNO3
(iii) Sulphuric acid H2SO4
(c) pH value equal than 7
(i) Sodium chloride NaCl
(ii) Potassium nitrate KNO3
(iii) Calcium chloride CaCl2
(iv) Water H2O
Q.2 Define a base and explain all alkalies are bases, but all bases are not alkalies.
Answer: Base: A base is a substance that can release OH‘ions in aqueous solution.
OR
A base is a substance that can accept a pair of electron.
OR
A base is a substance that can donate a pair of electrons.
Note:
“All alkalies are bases, but all bases are not alkali” because
Reason:
- Because water soluble bases are called Alkalies that’s why all the Alkalies are bases but all the bases are not Alkali
- Only the metal oxides of first group form metal hydroxides in water, are called alkalies while other metal hydroxides are called bases.
Q.3 Define Bronsted-Lowry base and explain with an example that water is a Bronsted
Lowry base.
Answer: Definition: A base is a substance that can accept a proton (H+) from another substance.
Water is an amphoteric substance it can be either act as acid and base.
In this reaction water is a base.