When viewing .pdfs online, there is a feature called fast web view. This is meant to help users by opening the first page of the .pdf before the rest of it has loaded, but sometimes this causes an error in Google Chrome. This results in only the first page being visible.
When creating exam questions, please ensure that any .pdfs created to not have fast web view enabled to ensure all students will be able to open the document in any browser.
To check to see if a .pdf has Fast View Enabled, look at the properties of the document (File > Properties). In the bottom right hand corner it will say Fast Web View Enabled: [Yes or No]
PDFs with Fast Web View are normally created from the Adobe suite of software tools. If you are creating a .pdf from Word you will not have this issue.
To disable fast view in Acrobat, go to Edit > Preferences > Documents > Save Settings > Save As optimizes for Fast Web View [deselect] .