The difference between "if" and "whether" lies in their usage. "If" is used in conditional sentences to express a possibility or condition. For example, "If it rains, I will stay at home." On the other hand, "whether" is used when presenting two alternatives or options. For instance, "I don't know whether to go to the party or stay home." Both words can introduce indirect questions. "Whether" is more formal and is commonly used in indirect questions. "If" can be used in both direct and indirect questions. Please, provide an example sentence in which you would like to see the correct usage of either "if" or "whether".