I believe the underlying issue is that when viewing questions inside the Moodle web interface, questions are ordered by question name, but when exporting, they are ordered by internal question ID instead (equivalent to date/time of creation). A workaround might be to export the questions using the Microsoft Word File Import/Export (Question Format) plugin instead. The questions are still in the wrong order, but you can use Word to sort them quite efficiently. The Word export format uses the "Heading 1" style for category names, and the "Heading 2" style for Question names. Turn on Outline view in Word (screenshot 1 below), and then set the "Show Level:" field to "Level 2" to view all "Heading 2" styles (i.e. the question names, screenshot 2 below). Select the Heading 2 styles within a category and use Home > Sort to sort them alphabetically.