Balance the reaction first:
3KOH + H3PO4 —> K3PO4 + 3H2O
So for every mol of H3PO4, you need 3 mol of OH- to fully neutralize the acid, since H3PO4 is polyprotic.
0.0200 L KOH • (2.000 mol KOH / L KOH) • (1 mol H3PO4 / 3 mol KOH) = 0.0133 mol H3PO4
Divide this by the volume of H3PO4 to get the concentration.
0.0133 mol H3PO4 / 0.0250 L = 0.532 M H3PO4
I think it’s I
Iodine has 53 protons and 74 neutrons
You can youse a calculator or ask a teacher
We have a 3-colour vision which happens to be the primary colours: red, blue and yellow. So, we can see red, and that is why we see it.
To see other we just mix the different cells as if we where mixing paint to get a new colour.
Hope it was easy to understand,
Happy homework/ study/ exam!