THE ANSWER OF ACIDS AND BASES QUIZ Part IV

1.      NH₃ + H₂O ↔ NH₄⁺ + OH^-

The correct statement is ….

1. NH₃ is acid
2. NH₄⁺ is conjugate acid of NH₃
3. H₂O is base
4. OH^- is conjugate base of NH₄⁺
5. NH₃-H₂O are conjugate acid and conjugate base

2.      H₂O + HCO₃^- ↔ H₂CO₃ + OH^-  The bases are ….

1. H₂O and HCO₃^-                
2. H₂CO₃ and H₂O
3. H₂CO₃ and OH^-   
4. H₂O and OH^-
5. HCO₃^- and OH^-          

3.      From the above equation, the correct statement is ….

a. H₂O is a weak acid      

b. HCO₃^- is neutral

c. OH^- is a weak base

d. H₂CO₃ is a weak acid

4.    H₂O + HCN  ↔  CN^- + H₃O⁺

In this equation ….

a.       HCN is a base

b.      H₂O and HCN are a weak base and a weak acid     

c.       H₃O⁺ is a base

d.      CN^- is a conjugate acid of HCN

5.      H₂O + HSO₄^-  ↔  SO₄^2- + H₃O⁺

The wrong statement is ….

a.       as an acid, HSO₄^- is weaker than H₃O⁺

b.      as a base, HSO₄^- is stronger than H₃O⁺

c.       as an acid, H₂O is weaker than H₃O⁺

d.      as a base, H₂O is stronger than SO₄^2-

6.      Known 5 equations below:

      1. H₂O + NH₃  ↔  NH₄⁺ + OH^-

      2. H₂O + HF  ↔  H₃O⁺ + F^-

      3. H₂O + NH₃  ↔  NH₂^- + H₃O⁺

      4. H₂O + HCN  ↔  CN^- + H₃O⁺

      5. H₂O + HSO₄^-  ↔  SO₄^2- + H₃O⁺

      According to Bronsted–Lowry, H₂O as an acid and a base are in number  ....

      a. 1 and 2

      b. 2 and 3

      c. 2 and 4

      d. 2 and 5

      e. 4 and 5

7.      The difference between acid and conjugate base is ….

a. a proton            

b. a neutron

c. an electron

d. a nucleus

8.      A substance that may act as both an acid and a base is ….

a. a hydride
b. a hydroxide
c. disproportionate
d. amphoteric                   
e. a salt

9.      Which of the following would be the most basic substance in aqueous solution?

a. HSO₄^-
b. F^-                      
c. I^-
d. Cl^-
e. NO₃^-

10.  Which of the following would be the most acidic substance in aqueous solution?

a. Na⁺                    d. SO₄^2-
b. H₂O                   e. NH₂^-
c. NH₄⁺     

11.  According to the Lewis theory, a base:

a.       is a proton acceptor.

b.      is a proton donor.

c.       makes available a share in a pair of electrons.         

d.      is any compound that contains electron pairs.

e.       accepts a share in a pair of electrons.

12.  Based on the reactions we have studied, ammonia can be considered as

a.       an Arrhenius base (only).

b.      a Lewis base (only).

c.       a Bronsted-Lowry base (only).

d.      both an Arrhenius base and a Lewis base.

e.       both a Bronsted-Lowry base and a Lewis base.    

13.  Which statement concerning the autoionization (self-ionization) of water is FALSE?

2 H₂O(l) <==> H₃O⁺ + OH^-(aq)

a.       This reaction is an acid-base reaction according to the Bronsted-Lowry theory.

b.      Water is amphiprotic.

c.       A H₂O molecule may react as an acid by donating a proton.

d.      In this reaction H₃O⁺ and OH^- are a conjugate acid-base pair          

e.       A H₂O molecule may react as a base by accepting a proton.