Chemistry - Acid & Base Question




Questions!


1.     Write the the acid-conjugate base pair from this spesi:
a)     H2O
b)     NH3
c)      CO32-
d)     HSO4-
              Answer:
              Each molecule add by one proton (H+)
a)     H3O+
b)     NH4+
c)      HCO3-
d)     H2SO4
2.     Identify each reactant and product as either a Bronsted-Lowry acid or a Bronsted Lowry base.
NH3 (g)       +       H2O (l)   -------->       NH4+ (aq)       +       OH– (aq)
                                          <--------
Answer:
NH3 (g)       +       H2O (l)  ------> NH4+ (aq)       +       OH– (aq)
Base                   Acid      <------ Acid conjugate            base conjugate
·         Acid : H2O      
·         Base :  NH3
·         H2O and OH–    = Acid and base conjugate
·         NH3 and NH4+  = Base and acid conjugate

3.     Continue this reaction and identify the acid base conjugate from the reaction.
a)     H2O (l)        +        HCl (aq)         D   …
b)     OH– (aq)        +        H3O+ (aq)        D        ….
            Answer :
 a.   H2O (l)        +        HCl (aq)      ------------>       H3O+ (aq)        +        Cl– (aq)
Base                acid                   <------------    acid conjugate                  base conjugate

·         Acid : HCl      
·         Base :  H2O
·         HCl and Cl–    = Acid and base conjugate
·         H2O and H3O+  = Base and acid conjugate

b.    OH– (aq)        +        H3O+ (aq)  ----------->  2 H2O (l)
                                                           <-----------
·         Acid : H3O+ 
·         Base : OH–
·         H3O+  and  H2O = Acid and base conjugate
·         OH– and H2O = Base and acid conjugate

4.What is the weakness of using litmus paper as the pH indicator?
Answer :
It ca only show us that the substances are acid or base. It cannot show us the pH value of the substances.

5.What is the advantage of using universal indicator rather that uses litmus paper?
Answer :
It can show us the pH value of the substances through the color change of the universal indicator. It is more accurate than litmus.



      




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