Question:
Which of the following is a conjugate acid-base pair?
Which of the following is a conjugate acid-base pair?
Show Hint
Remember, to identify a conjugate acid-base pair, look for substances that can directly form each other by transferring a proton.
Updated On: May 31, 2026
- $\text{NH}_4^+$ and $\text{NH}_3$
- $\text{HCl}$ and $\text{NaOH}$
- $\text{H}_2\text{SO}_4$ and $\text{SO}_4^{2-}$
- $\text{HNO}_3$ and $\text{H}_2\text{O}$
Show Solution
Verified By Collegedunia
The Correct Option is A
Solution and Explanation
Step 1: Concept
In an acid-base reaction, the conjugate base of an acid is the species formed when the acid donates a proton (H$^+$), and the conjugate acid of a base is the species formed when the base accepts a proton. For example, if $\text{NH}_3 + \text{H}^+ \rightarrow \text{NH}_4^+$, then $\text{NH}_4^+$ is the conjugate acid of $\text{NH}_3$.
Step 2: Meaning
A conjugate acid-base pair consists of a substance and its reaction product after it has gained or lost a proton. The key to identifying such pairs lies in recognizing which molecule can donate a proton (acid) and which can accept one (base).
Step 3: Analysis
Let's analyze each option: Option A: $\text{NH}_4^+$ and $\text{NH}_3$ - $\text{NH}_4^+$ is formed when $\text{NH}_3$ donates a proton. Therefore, $\text{NH}_3$ acts as the base (accepts H$^+$) and $\text{NH}_4^+$ acts as its conjugate acid. Option B: $\text{HCl}$ and $\text{NaOH}$ - These are not a conjugate pair because they do not directly form each other by proton transfer. Instead, $\text{HCl}$ is an acid that can donate H$^+$ to $\text{NaOH}$ (a base), forming water and sodium chloride. Option C: $\text{H}_2\text{SO}_4$ and $\text{SO}_4^{2-}$ - $\text{H}_2\text{SO}_4$ can donate protons to form $\text{HSO}_4^-$, but not directly to $\text{SO}_4^{2-}$ in a simple proton transfer reaction. Thus, they are not a conjugate pair. Option D: $\text{HNO}_3$ and $\text{H}_2\text{O}$ - These do not form each other by proton transfer. $\text{HNO}_3$ is an acid that can donate H$^+$ to water, but this does not make them a conjugate pair.
Step 4: Conclusion
The only option where one species directly forms the other through a simple proton transfer reaction is Option A: $\text{NH}_4^+$ and $\text{NH}_3$. Final Answer: (A)
Was this answer helpful?
0
0
Top AP EAPCET Chemistry Questions
- The four quantum numbers of the valence electron of potassium are :
- The volume of $0.02\, M$ acidified permanganate solution required for complete reaction of $60\, mL$ of $0.01\, MI^{-}$ ion solution to form $I_2$ in $mL$ is
- In which of the following the election gain enthalpy of elements is correctly arranged?
- The radii of $ \text{F,}{{\text{F}}^{-}}\text{O} $ and $ {{\text{O}}^{2-}} $ are in the order
- Which of the following has the highest first ionization potential?
View More Questions
Top AP EAPCET Ionic Equilibrium In Solution Questions
- The pH of 0.01M BOH solution is 10. What is its degree of dissociation? (Given $ K_b $ of BOH is $ 1 \times 10^{-6} $)
- At T(K), the solubility products (K\(_{sp}\)) of AgCl, AgBr and AgI are \(1.8 \times 10^{-10}\), \(5 \times 10^{-13}\) and \(8.3 \times 10^{-17}\) respectively. A 1L solution contains \(10^{-5}\) moles each of NaCl, NaBr and NaI. This solution is titrated with \(10^{-6}\) M AgNO\(_3\) until all halides (Cl\(^{-}\), Br\(^{-}\), I\(^{-}\)) are precipitated as silver salts.
The order of precipitation of these respectively is: - The pH of a $0.01\text{ M NaOH}$ solution is}
- The pH of a 0.1 M solution of a weak monobasic organic acid is 4.0. What is the dissociation constant of the acid?
Top AP EAPCET Questions
- A body is projected from the ground at an angle of $\tan^{-1} \left( \frac{8}{7}\right)$ with the horizontal. The ratio of the maximum height attained by it to its range is
- The four quantum numbers of the valence electron of potassium are :
- A lens forms real and virtual images of an object, when the object is at $u_{1}$ and $u_{2}$ distances respectively. If the size of the virtual image is double that of the real image, then the focal length of the lens is (take, the magnification of the real image as $m$ )
- Two spheres $P$ and $Q$, each of mass $200\, g$ are attached to a string of length one metre as shown in the figure. The string and the spheres are then whirled in a horizontal circle about $O$ at a constant angular speed. The ratio of the tension in the string between $P$ and $Q$ to that of between $P$ and $O$ is $(P$ is at mid-point of the line joining $O$ and $Q$ )
- The volume of $0.02\, M$ acidified permanganate solution required for complete reaction of $60\, mL$ of $0.01\, MI^{-}$ ion solution to form $I_2$ in $mL$ is
View More Questions