Which of the following chemicals destroys vitamin B when cooking vegetables and should be avoided?

Baking soda is known to destroy vitamin B when cooking vegetables primarily because it raises the pH level of the cooking water, creating an alkaline environment. Some vitamins, particularly vitamin B and vitamin C, are sensitive to changes in pH. In an alkaline environment, these vitamins can degrade and diminish in nutritional value.

When vegetables are cooked with baking soda, not only might their texture change, becoming mushy, but also the essential nutrients can be lost. This detrimental effect is particularly pronounced in the case of water-soluble vitamins, which includes several of the B vitamins.

In contrast, other options like salt, lemon juice, and vinegar do not have the same adverse effect on vitamin B content. Salt is often used to enhance flavor without significantly impacting nutrient loss, while lemon juice and vinegar may even help preserve nutrients due to their acidity, which can inhibit the breakdown of vitamins during cooking.