For 2 & 3 neither use "if and only if" so I am interpreting those two as intentially unsound syllogisms. Do people commonly expand "if" to mean "if and only if

For 2 & 3 neither use "if and only if" so I am interpreting those two as intentially unsound syllogisms. Do people commonly expand "if" to mean "if and only if" outside of a conversational setting where it's implied? I would think in a small body of text people would only refrane from doing so. I'd be interested in having the per syllogism results to see if this impacted the accuracy of the respondents.