Question

a physical change can sometimes result in a color change. which of the following situations shows this?
choose one option
a milk turns yellow when it spoils.
b dough becomes darker when it is baked into cake.
c a red candy dissolves and turns water pink.
d a match turns black when it is burned.

Explanation:

A physical change is a change in which no new substances are formed. When a red candy dissolves in water and turns it pink, it is just a dissolution process (a physical change). The candy's color spreads in water, but no new chemical substances are created.

• When milk spoils (A), it is a chemical change as new substances (like spoilage - related compounds) are formed due to bacterial action.
• When dough becomes darker when baked into cake (B), it is a chemical change (Maillard reaction etc., where new flavor and color compounds are formed).
• When a match turns black when burned (D), it is a chemical change (combustion reaction, new substances like carbon (from incomplete combustion) etc. are formed).

Answer:

C. A red candy dissolves and turns water pink