Which fits better in these sentences and why?

Who/Whom painted that big mural in the post office.

Do you know who/whom the secretary of state is?

Use "who" when the pronoun is the subject. Use "whom" when it is any type of object.

I'm not sue but I would put who because it's a simpler word

To determine whether to use "who" or "whom" in these sentences, we need to understand the difference between the two.

"Who" is used as a subject pronoun, meaning it is the doer of the action in the sentence. For example, "Who painted that big mural" refers to the person who performed the action of painting.

"Whom" is used as an object pronoun, meaning it is the receiver of the action in the sentence. For example, "Whom did you see at the park?" refers to the person who is the object of the verb "see."

Now, let's analyze the sentences:

1. Who/Whom painted that big mural in the post office.
In this sentence, the person who painted the mural is the subject of the verb "painted." To determine the correct pronoun, you can rephrase the sentence as a question and answer it. "Who painted that big mural?" The answer would be something like, "He painted it." Since "he" is a subject pronoun, we should use "who" in the original sentence. Therefore, the correct choice is "Who painted that big mural in the post office?"

2. Do you know who/whom the secretary of state is?
In this sentence, "the secretary of state" is the object of the verb "know." To determine the correct pronoun, you can rephrase the sentence as a question and answer it. "Who do you know?" The answer would be something like, "I know him." Since "him" is an object pronoun, we should use "whom" in the original sentence. Therefore, the correct choice is "Do you know whom the secretary of state is?"

In both cases, the choices are "who" and "whom." "Who" is used when the pronoun is the subject of the verb, and "whom" is used when the pronoun is the object of the verb.