Yes indeed it is:
- Right Click project
- Select Properties
- Select Configuration Properties
- General
- Platform Toolset
When you get to Platform Toolset, click on the v110 value which will be in the right column. You will see a drop down appear which will allow you to select v90, v100, or inherit. Of course, v100 is the correct answer. Once v100 is selected, I don’t believe you can back to v110 from within VS 2010. You would have to once again open in in VS 2012 to move it back to v110.