Would you like a chocolate? (If I offer to taste one chocolate from a box.)
Would you like some chocolate? (If I offer to taste a bar of chocolate.)
Is it correct?
Would you like a chocolate? (If I offer to taste one chocolate from a box.)
Would you like some chocolate? (If I offer to taste a bar of chocolate.)
Is it correct?
Yes, "chocolate" is often used both as a countable and as a mass noun.
"Chocolate" as a mass noun refers to the substance, in the same way as "butter" or "flour," and we can talk about "some chocolate" (a certain quantity of the substance).
"Chocolate" as a countable noun can be thought of as short for "a piece of chocolate." We might have a box of chocolates (individual pieces, e.g. truffles) and we can give someone a chocolate.
This doesn't apply to all substances; we never say "a box of butters" or "would you like a flour."