Chemistry Ch.# 10

Wisdom Academy

Chemistry

Chapter 10

10.1

i. What is the difference b/w Arrhenius and Bronsted-Lowry base?

Ans. According to Arrhenius Base is a compound which gives hydroxide ions (OH^-) in its aqueous solution. The general equation is:

           BOH_(aq)    ⥨   B⁺_(aq)    +    OH^-_(aq)

         According to Bronsted-Lowry concept “A base is a substance that can accept proton (H⁺) from another substance. The equation is:

         HCl_(aq)     +   NH_3(aq)(Base)     ⥨   NH_4­⁺_(aq)      +     Cl^-_(aq)

ii. What do you mean by neutralization reaction according to Arrhenius acid-base concept?

Ans. When acid reacts with base it forms water and salt it is called neutralization according to Arrhenius Acid-Base concept.

For Example:

     HCl    +    NaOH    ⟶   NaCl   +   H₂O

iii. Prove that water is an amphoteric specie?

Ans. Water is an Amphoteric specie because it act as both acid and base.

As an Acid:

             H₂O        +    NH₃         ⥨       NH₄⁺      +    OH^-

As a Base:

             HCl       +     H₂O       ⥨         H₃O⁺        +         Cl^­-

iv. How can you justify that NH₃ is Bonsted-Lowry base but not Arrhenius base?

Ans. According to Bronsted-Lowry Base is a substance which can accept a proton (H⁺) from another substance. But according to Arrhenius concept Base is a substance which gives hydroxide ions when dissociates in a aqueous solution. NH₃ does not gives hydroxide ions in aqueous solution but it accept a proton from another substance. So, it is a Bronsted-Lowry base but not a Arrhenius Base.

v. State and explain neutralization reaction according to Lewis Concept?

Ans. According to Lewis concept neutralization reaction is a reaction  in which donation and acceptance of an electron pair takes place to form a coordinate covalent bond in an adduct.

                               NH₃ + BF₃  ⟶ [NH₃⟶BF₃]

vi. Define and give the characteristics of Lewis Acid?

Ans. According to Lewis “acid is a substance which can accept a pair of electron”.

1)   Lewis acid is a substance which accept a pair of electron.

2)  Lewis Acid form a coordinate covalent bond with other substance in order to accept a pair of electron.

vii. Why BF₃ act as Lewis Acid?

Ans. BF₃ acts as Lewis Acid because it accept a pair of electron from another substance which act as Lewis Base.

For Example:

               NH₃    +    BF₃  ⟶  [NH₃⟶BF₃]

Here BF₃ accept two electrons and act as Lewis Acid.

Viii. Water is an amphoteric specie according to Bronsted-Lowry concept. What is its nature according to Lewis Concept?

Ans. According to Lewis concept Water act as  Base. Because it gives a pair of electron to hydrogen ion H⁺ and becomes hrdronium ion H₃O⁺.

                 H⁺     +       H₂O     ⟶   [H₃O]⁺

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