The correct option is B.
Phenophtalein is an indicator that is usually used in acid base titration experiments. Indicators are substances that undergo distinct, observable changes when the pH of their solutions change. Indicators exhibit changing of colors depending on the pH of the solution in which they are found. They are usually weak bases and acid which are capable of partial dissociation and formation of ions when dissolved in water. There are different types of indicator and phenophtalein is one of them. Phenophtalein is colorless in acidic solution and pink in basic solutions.
I would suggest you to use this instead.
Just place the known substance for example O2 Oxygen as they are asking you, and see where the diagram takes you.
So the answer would be 2 because you’d look at the coefficients of the balanced equation up there. H2O
I hope that was helpful, if you have more questions please ask!
Lewis had proposed that the valence electrons of any substance were arranged around its atoms in a cubic configuration. Later on, this was modified when it was learned that the electrons actually orbit the nucleus, similar to the planets orbiting the sun. Moreover, it is now deduced that the electrons are found in regions, known as electron clouds, and their specific, discrete location at a given point in time can not be determined.
In commensalism the smaller partner benefits from the relationship, with no fitness effect on the host. There are fitness gains for both partners in mutualism, and a parasite benefits by exploiting but not directly killing its host.
hope this helps ^^