Answer: -
Baking soda having a pH of 9, has the maximum number of hydroxide ions.
Explanation: -
More the pH of a solution, the more basic it is and more the number of hydroxide ions it has.
From the question we find that
baking soda has a pH = 9
milk has a pH = 6
tomato juice has a pH = 3.5
vinegar has a pH = 2
Thus among them baking soda has the highest pH.
So baking soda is the most basic and has the maximum number of hydroxide ions.
To answer this question, we can use the following equation:

where e is the energy change, h is Planck's constant, c is the speed of light (m/s), and lambda is wavelength in meters. So then we can plug in the information:



So the energy that is omitted by the atom is
.
The oxidation number of chlorine in the reactant can be determined by K ion and O ion. K ion is +1 and O ion is -2. And the Cl is +5. The gas has the greatest entropy and the solid has the least. In the production, there are solid and gas. So it has more entropy than the reactants with solid only.