Write the conjugate acids for the following Brönsted bases : NH2-, NH3, HCOO-
NH3, NH4+, HCOOH
Understanding Brönsted-Lowry Acid-Base Theory
The Brönsted-Lowry theory defines an acid as a proton (H+) donor and a base as a proton acceptor. When a Brönsted base accepts a proton, it forms its conjugate acid. Conversely, when a Brönsted acid donates a proton, it forms its conjugate base.
To find the conjugate acid of a given Brönsted base, we simply add one proton (H+) to the base. The charge of the resulting species will increase by +1.
Finding the Conjugate Acids for Given Brönsted Bases
Let's find the conjugate acid for each of the given Brönsted bases: NH2-, NH3, and HCOO-.
- For the base NH2-:
Adding a proton (H+) to NH2-:
\(\text{NH}_2^- + \text{H}^+ \rightarrow \text{NH}_3\)
The conjugate acid of NH2- is NH3.
- For the base NH3:
Adding a proton (H+) to NH3:
\(\text{NH}_3 + \text{H}^+ \rightarrow \text{NH}_4^+\)
The conjugate acid of NH3 is NH4+.
- For the base HCOO-:
Adding a proton (H+) to HCOO- (formate ion):
\(\text{HCOO}^- + \text{H}^+ \rightarrow \text{HCOOH}\)
The conjugate acid of HCOO- is HCOOH (formic acid).
Comparing Results with Options
We found the conjugate acids for the given Brönsted bases in the order NH2-, NH3, HCOO- to be NH3, NH4+, and HCOOH.
Let's look at the options provided:
- Option 1: NH3, NH4+, HCOOH
- Option 2: N3-, NH3, \(\rm HCO^-_2\)
- Option 3: NH4+, NH3, CO2
Comparing our calculated conjugate acids (NH3, NH4+, HCOOH) with the options, we see that Option 1 matches our results exactly in the correct order corresponding to the given bases.
Therefore, the conjugate acids for NH2-, NH3, HCOO- are NH3, NH4+, HCOOH respectively.
Important Questions from Concepts of Acids and Bases
The order of correct acidic strengths of halogen acids is
The base ionization constant, Kb, of ammonia in water is 1.8 × 10-5. The value of the acid ionization constant, Ka, of the conjugate acid, is closest to
- Which of the following chemical reaction is example for Lux-Flood definition ?
- A sample of soil mixed with water turns the pH paper yellowish orange. Which of the following would now change the colour of the pH paper to bluish?
- Read the statements given below and choose the correct option :
Assertion (A): It is recommended that acid should be added to water for diluting the acid and not vice-versa.
Reason (R) : Dilution of acid is a highly exothermic reaction.
