Question

What is the pH range of milk?

• A. 7.2 - 7.5
• B. 9.2 - 9.5
• C. 6.7 - 6.9
• D. 3.4 - 3.9

Hint:

Fresh milk is slightly acidic (just below the neutral mark of 7). Remembering this fact helps you easily eliminate basic options (above 7) and highly acidic options (under 5).

Answer 1

The Correct Option is C

Step 1: Understanding the Question:
The question asks for the standard pH range of milk to determine its acidic or basic nature.

Step 2: Detailed Explanation:
1. The pH scale ranges from 0 to 14, where 7 is neutral. Values below 7 indicate acidity, while values above 7 indicate alkalinity (basicity).
2. Fresh cow's milk is slightly acidic, generally falling within the range of 6.5 to 6.7 (broadly classified between 6.4 and 6.8).
3. Over time, as milk sits, lactose (milk sugar) is converted into lactic acid by bacteria, which increases the acidity and lowers the pH further, leading to souring.
4. Let us evaluate the options provided:
(A) 7.2 - 7.5: This range is slightly basic, which does not represent fresh milk.
(B) 9.2 - 9.5: This range is highly basic.
(C) 6.7 - 6.9: This range is slightly acidic to nearly neutral, which is the closest and most appropriate range for fresh milk among the options.
(D) 3.4 - 3.9: This range is highly acidic, typical of citrus juice or vinegar, and is far too low for consumable fresh milk.
5. Therefore, the pH range of 6.7 - 6.9 is the most accurate choice.

Step 3: Final Answer:
The pH range of milk is 6.7 - 6.9.