<span>C12H22O11. If it is a dehydration reaction, there is a union of the two monosaccharides and a water molecule is lost. So double the C6H12O6, and remove an H2O, so C12H24O12 - H2O would yield C12H22O11.</span>
Place a burning splint near the opening of a test tube. If a popping noise occurs, it's probably hydrogen. Place a glowing splint in the test tube, and if it reignites, it could be oxygen. Place a burning splint into a test tube, and if it goes out, it could be carbon dioxide.