Final answer:
Impurities are always undesired in a material. They can affect the structure and properties of a solid by disrupting the regular arrangement of atoms or molecules in the crystal lattice. There for the answer is True.
Step-by-step explanation:
Impurities are always undesired in a material. True.
Impurities can affect the structure and properties of a solid. The presence of impurities can disrupt the regular arrangement of atoms or molecules in the crystal lattice, thereby altering the physical and chemical properties of the solid. For example, impurities in metals can reduce their strength and conductivity, while impurities in semiconductors can modify their electrical behavior and make them suitable for specific electronic applications.
Additionally, the deliberate addition of controlled impurities, known as doping, is used to alter the electrical conductivity of semiconductors, which is crucial for the operation of electronic devices.