Among the options provided, caustic soda has the highest pH value. Let’s break down the pH levels of each substance:
- Lime Juice: Typically has a pH of around 2 to 3, making it acidic.
- Wine: Generally has a pH ranging from 3 to 4, also placing it in the acidic category.
- Water: Pure water has a neutral pH of about 7.
- Caustic Soda: This is a strong base (sodium hydroxide) and can have a pH of 13 or higher.
In summary, the acidic substances (lime juice and wine) have low pH values, while pure water is neutral. Caustic soda, being a strong base, stands out with a significantly higher pH level, making it the clear answer to the question.