"Unstructured questions” are the open-ended questions. They are different from the “Structured questions” in the sense that these questions (structured) are closed-ended questions, which can either be a two-way question or a multiple choice question.
open-ended (unstructured) questions gives more freedom of expression to the respondents, but they are difficult to interpret and to score, whereas close ended (structured) questions are easy to use, score and to codify for analysis, because the options/answers are given and the respondents have to choose from them only.