Question

1)Explain,why we cannot call any fresh vegetable or fruit a pure substance?

Answer 1

We cannot consider fresh fruits and vegetables as pure substances. As pure substances are made up of only one kind of matter but if you see vegetables and fruits they are not made up of one kind of matter for example if you take an apple, its compositions includes water, proteins, lipids, carbohydrates, organic acids, fiber …… Hence it is a mixture (combination of two or more pure substances) and not a pure substance.

These compositions of apples have varying physical and chemical properties (i.e., boiling point and melting point), and can be separated in to pure components while a pure substances have constant physical and chemical properties and cannot be physically separated as they are already in their basic form. The same is applicable for vegetables.
Hence fresh fruits and vegetables are mixtures and not pure substances.