How do I know whether a base is strong or not?

  • Chemistry
  • Thread starter simphys
  • Start date
  • Tags
    Base
In summary, the conversation discusses determining the strength of acids and bases. While there is a table available for determining strong acids based on their pKa values, there is no such table for bases. However, some metal hydroxides, such as alkali metal hydroxides and alkaline earth metal hydroxides, are generally considered to be strong bases. The conversation also mentions that Kb values for metal hydroxides are difficult to find, but pKb values for certain bases, such as ammonia, are known.
  • #1
322
45
Homework Statement
that is the question.
Relevant Equations
chemistry
So I know that I can get whether an acid is strong or not from a table where if ##pK_a## < 0 than it is a strong acid, but there is no such table for bases, so how do I determine whether a base is strong or weak?

Also.. for metalhydroxides MOH, which will be strong and which are weak bases?
Thanks in advance!
 
Physics news on Phys.org
  • #2
or.... do we consider all of the metalhydroxides (that do not hydrolise) to be strong bases because they will form OH- ions which is basically considered a strong base?
 
  • #3
simphys said:
there is no such table for bases

Sure there are, how do you think I know pKb for ammonia is 4.75?

But you are right that Kb values for metal hydroxides are quite difficult to find. That's because they are not that important - most hydroxides are either very strong bases (alkali metal hydroxides are very strong, alkaline earth metal hydroxides are strong and almost fully dissociated, but poorly soluble) or so insoluble discussing their strength is a moot.
 

1. What is the definition of a strong base?

A strong base is a substance that completely dissociates into ions when dissolved in water, producing a high concentration of hydroxide ions (OH-) and a low concentration of hydronium ions (H3O+).

2. How can I determine the strength of a base?

The strength of a base can be determined by measuring its pH level. A strong base will have a pH of 12-14, indicating a high concentration of hydroxide ions.

3. What are some examples of strong bases?

Sodium hydroxide (NaOH), potassium hydroxide (KOH), calcium hydroxide (Ca(OH)2), and barium hydroxide (Ba(OH)2) are all examples of strong bases.

4. Can a base be both strong and weak?

No, a base can only be classified as strong or weak. However, some substances may exhibit both basic and acidic properties, making them amphoteric.

5. How does the strength of a base affect its properties?

A strong base will have a higher reactivity with acids, a higher ability to neutralize acids, and a higher corrosiveness compared to a weak base. It will also have a higher conductivity and a higher solubility in water.

Suggested for: How do I know whether a base is strong or not?

Replies
1
Views
2K
Replies
7
Views
1K
Replies
1
Views
718
Replies
14
Views
2K
Replies
1
Views
1K
Replies
6
Views
2K
Replies
1
Views
1K
Back
Top