Which ionic compound dissolves in water to form a colored solution

What is the empirical formula of vanadium 1 oxide given that 20.38 grams of vandium combines with oxygen to form 23.58 grams of the oxide

Consider the reaction of a(g) + b(g) + c(g) => d(g) for which the following data were obtained: experiment initial [a], mol/l initial [b], mol/l initial [c], mol/l initial rate, mol/l.s 1 0.0500 0.0500 0.0100 6.25 x 10^-3 2 0.100 0.0500 0.0100 2.50 x 10^-2 3 0.100 0.100 0.0100 1.00 x 10^-1 4 0.0500 0.0500 0.0200 6.25 x 10^-3 what is the rate law for the reaction?

What is the ph of a solution that has a hydrogen ion concentration of 1.0 * 10 -9 m?