If and whether are two words that may sometimes be used interchangeably, but are not always interchangeable. If and whether are conjunctions, which are words that connect two or more sentences, clauses, or parts of clauses. Some of the most common conjunctions in English are and, because, but, for, nor, so, until, when, and yet. Understanding the parts of speech such as verbs, nouns, pronouns, adverbs and adjectives in grammar will improve your English communication skills. We will examine the ways in which the conjunctions if and whether should be used, as well as some examples of how to use them in sentences.
Sometimes, the words if and whether are interchangeable, especially when using informal language:
Jamie called the restaurant to see if it was open.
Jamie called the restaurant to see whether it was open.
These sentences mean the same thing. However, using the word if in this manner is considered informal language.
The conjunction if must be used in a conditional sentence. A conditional sentence is one in which the outcome depends on a certain circumstance, or where a situation is hypothetical:
We can play outside if the sun comes out.
Beggars would ride if wishes were horses.
The conjunction whether must be used when there are two alternatives or a choice:
I don’t know whether he prefers daffodils or marigolds.
It doesn’t matter whether you read the book tonight or tomorrow night.
Additionally, whether must always be used when it precedes an infinitive with the word to:
I am unsure whether to accept a ride from that gentleman.
Have you decided whether to go to college?
The conjunction whether is also used after a preposition:
Jamie was concerned about whether to close the window.
The answer depends on whether you ask the right question.
The word if is derived from the Old English word gif, meaning so or if. The word whether is derived from the Old English words hwæther and hwether, which mean which of two.
Remember, if is used when the sentence is conditional. Whether is used when the sentence is discussing a choice or two alternatives and is used before an infinitive using the word to and after a preposition.