It should be 0.25 M. Use the formula C1*V1=C2*V2, for those values, as it is right when it changed colour. Remember to change the if those are not the same (but in your case it is, so no need this time).
C1*V1=C2*V2
C1*27ml=0.55M*12.5ml
C1=(0.55M*12.5ml)/27ml = 0.25M
Carbohydrates are biological molecules made of carbon, hydrogen, and oxygen in a ratio of roughly one carbon atom (
C
Cstart text, C, end text) to one water molecule (
H
2
O
H
2
Ostart text, H, end text, start subscript, 2, end subscript, start text, O, end text). This composition gives carbohydrates their name: they are made up of carbon (carbo-) plus water (-hydrate). Carbohydrate chains come in different lengths, and biologically important carbohydrates belong to three categories: monosaccharides, disaccharides, and polysaccharides.
