If you are given the
standard potential for the reduction of X^2+ is +0.51 V, and the standard
potential for the reduction of A^2+ is -0.33, just add the two. The standard
potential for an electrochemical cell with the cell is 0.18V
When oxygen is found is peroxide, it has an oxidation number of -1.
The chemical formula of hydrogen peroxide is H2O2. We know that hydrogen always has +1 oxidation state until it forms metal hydrides. So in H2O2, the oxidation state ofhydrogen is +1.
Now, let oxidation state of oxygen be x. So,
2 * (+1) + 2*x = 0
2 + 2x = 0
2x = -2
x = -2 / 2
x = -1
Hence, the oxidation number of oxygen in peroxides is -1
Blue litmus paper turning red means that the solution where the litmus paper was submerged is an acidic solution with a pH of less than 7. Another verification of the nature of the solution is the turning to red of methyl orange in acidic solutions. The answer then is D.
B. the frogs are a limiting factor for the gnats
the frogs limit the reproduction of the gnats, and therefore with less frogs the gnat population can increase
