Apple juice is classified as a mixture. This is because it contains various components that are not chemically bonded together. When you press apples to extract juice, you obtain not just the liquid from the apples, but also suspended particles like pulp, fiber, and other compounds that are naturally present in the fruit.
A pure substance, on the other hand, is a material with a uniform and definite composition; it cannot be separated into different substances through physical means. While pure apple juice can be obtained through processes like filtration to remove pulp, the typical juice you find in stores often contains additional ingredients (like water, preservatives, or sugar) which further supports its classification as a mixture. Therefore, unless it is entirely clear and devoid of any solids or additives, apple juice remains a mixture.