<h3>
Answer:</h3>
1.380 × 10^-8 M
<h3>
Explanation:</h3>
The pH is the measure of alkalinity or acidity of a substance.
It is the negative logarithm of H+ ions concentration [H+].
pH = -log[H+]
pOH on the other hand is negative logarith of OH- concentration [OH-].
pOH = -log[OH-]
In this case;
pOH = 7.86
We can calculate the [OH-]
pOH = -log[OH-]
But, pOH = 7.86
pOH = -log[OH-]
-log[OH-] = 7.86
[OH-] = Antilog -7.86
= 1.380 × 10^-8 M
Therefore, [OH-] is 1.380 × 10^-8 M
The answer is Ga.
That is gallium (Ga), correctly names the element that Mendeleev predicted would be discovered and placed in the aluminum column.
Gallium (Ga) is the element that Mendeleev predicted would be discovered and placed in the aluminum column.
So the answer is Gallium (Ga) that is there in the 13th group of periodic table or in aluminium column.