a) Assertion: Acidulates are added in soft drinks to provide a buffering action. r) Reason: Buffers tend to prevent changes in pH and prevent excessive tartness. Choose the correct answer from the following
Soft Drink Acidulants and Buffering Action Explained
This question relates to the chemical properties of soft drinks, specifically the role of acidulants and buffering.
Assertion Analysis (a)
The assertion states that acidulants are added to soft drinks to provide a buffering action. Acidulants, such as phosphoric acid or citric acid, are primarily added for tartness and flavor enhancement. However, these weak acids, along with their conjugate bases potentially present in the drink, can contribute to a buffer system. This system helps stabilize the drink's pH.
Therefore, the assertion that acidulants provide a buffering action is considered true in the context of their contribution to the drink's chemical stability.
Reason Analysis (r)
The reason explains that buffers prevent changes in pH and excessive tartness. This is a fundamental definition of a buffer solution. Buffers resist drastic shifts in acidity or alkalinity when small amounts of acids or bases are added.
In beverages, maintaining a stable pH is crucial for taste consistency and preventing the flavor profile from becoming overly sharp or sour (excessively tart). Thus, the reason is factually true.
Relationship Between Assertion and Reason
The reason explains the function of buffers. Since the acidulants added to soft drinks contribute to a buffer system (as established in the assertion analysis), the function described in the reason directly relates to why this buffering action is important. Preventing excessive tartness and stabilizing the pH are key benefits derived from the buffering action provided, in part, by the acidulants.
Therefore, the reason (r) is a correct explanation for the assertion (a).
Conclusion
Both the assertion and the reason are true, and the reason correctly explains the assertion.
Important Questions from Chemical Biology {p}K_a Henderson Hasselbalch
- The equilibrium dissociation constant of acetic acid is $1.74 \times 10^{-5}$ $M$. The $pK_a$ of acetic acid (rounded off to one decimal place) is ________.
- The ionic product of water at $40$ °C is $2.92 \times 10^{-14}$ $M^2$. The pH of water at $40$ °C is ________ (rounded off to 2 decimal places).
- In a lactic acid solution at pH $4.8$, the concentrations of lactic acid and lactate are $0.01$ M and $0.087$ M, respectively. The calculated pKa of lactic acid is ________ (Round off to one decimal place)
An aqueous solution of aspirin (HA) is prepared at pH 7.4. The ratio of concentration of $A^-$ and HA at equilibrium is ________ (round off to the nearest integer).
Given: $K_a$ of aspirin is $3.98 \times 10^{-4}$
- If 50 mL of 0.02 M HCl is added to 950 mL of $H_2O$, then the pH of the final solution will be _________
