Class XII students were asked to prepare one litre of buffer solution of pH \(8.26\) by their Chemistry teacher. The amount of ammonium chloride to be dissolved by the student in \(0.2\) M ammonia solution to make one litre of the buffer is (Given : \(pK_b\) \((NH_3)\) = \(4.74\), Molar mass of \(NH_3\) = \(17\) g \(mol^{–1}\), Molar mass of \(NH_4Cl\) = \(53.5\) \(g\) \(mol^{–1}\))
- 53.5 g
- 72.3 g
- 107.0 g
- 126.0 g
The Correct Option is C
Solution and Explanation
For basic Buffer,
\(pOH=pK_b+log\frac{[salt]}{[Base]}\)
\(pOH=14–8.26=5.74\)
\(5.74=4.74+log\frac{[NH_4Cl]}{0.2}\)
\([NH_4Cl]=2 M\)
Moles of \( NH_4Cl = 2 × 1 = 2 \) \(moles\)
Weight of \(NH_4Cl\) = \(2 × 53.5 = 107\) \(g\)
Top Questions on Buffer Solutions
- In a Bowler's solution containing the same concentrations of B- and HB, the ratio of KB to B- is 10-10. The pH of the Bowler's solution will be:
- BCECE - 2025
- Chemistry
- Buffer Solutions
- The pH of a mixture containing 100 mL of 0.5 M acetic acid and 50 mL of 0.2 M NaOH is (p\(K_a\) of CH\(_3\)COOH = 4.8).
(Given: \( \log 3 = 0.48 \), \( \log 4 = 0.60 \))- AP EAPCET - 2025
- Chemistry
- Buffer Solutions
- Only litre buffer solution was prepared by adding 0.10 mol each of $ NH_3 $ and $ NH_4Cl $ in deionised water. The change in pH on addition of 0.05 mol of HCl to the above solution is _____ $ \times 10^{-2} $, (Nearest integer) (Given : $ pK_b $ of $ NH_3 = 4.745 $ and $ \log_{10}3 = 0.477 $)
- JEE Main - 2025
- Chemistry
- Buffer Solutions
- What is the Reimer Tieman reaction?
- KEAM - 2025
- Chemistry
- Buffer Solutions
- 100 mL of 0.1 M HA (weak acid) and 100 mL of 0.2 M NaA are mixed. What is the pH of the resultant solution? \((K_a \text{ of HA is } 10^{-5}, \log 2 = 0.3)\)
- AP EAMCET - 2024
- Chemistry
- Buffer Solutions
Questions Asked in JEE Main exam
- The sum of all rational numbers in \( (2 + \sqrt{3})^8 \) is:
- JEE Main - 2025
- Binomial theorem
- The maximum covalency of a non-metallic group 15 element 'E' with the weakest E-E bond is:
- JEE Main - 2025
- Group 15 Elements
Let one focus of the hyperbola $ \frac{x^2}{a^2} - \frac{y^2}{b^2} = 1 $ be at $ (\sqrt{10}, 0) $, and the corresponding directrix be $ x = \frac{\sqrt{10}}{2} $. If $ e $ and $ l $ are the eccentricity and the latus rectum respectively, then $ 9(e^2 + l) $ is equal to:
- JEE Main - 2025
- Conic sections
The largest $ n \in \mathbb{N} $ such that $ 3^n $ divides 50! is:
- JEE Main - 2025
- Number Systems
- For an experimental expression \( y = \frac{32.3 \times 1125}{27.4} \), where all the digits are significant. Then to report the value of \( y \), we should write:
- JEE Main - 2025
- Significant figures
Concepts Used:
Buffer solutions
The buffer solution is a solution that is able to maintain its Hydrogen ion concentration (pH) with only minor changes on the dilution or addition of a small amount of either acid or base. They are used in fermentation, food preservatives, drug delivery, printing, the activity of enzymes and many more.
Buffer solutions are aqueous solutions containing a weak acid and its salt - acid buffer or a weak base and its salt - base buffer.
Types of Buffer Solution
Acidic Buffers
These solutions are used to maintain acidic environments. Also, it has acidic pH and is prepared by mixing a weak acid and its salt with a strong base. An aqueous solution of an equal concentration of acetic acid and sodium acetate has a pH of 4.74.
Alkaline Buffers
These solutions are used to maintain basic conditions. It has a basic pH and is prepared by mixing a weak base and its salt with strong acid. The aqueous solution of an equal concentration of ammonium hydroxide and ammonium chloride has a pH of 9.25.