The answer is 10-12. The relationship of pH and [H+] is pH = -lg[H+]. And the higher pH, the stronger base is. So the strongest base has the lowest concentration of H+.
The variable that stays the same in an experiment is called the controlled variable
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Answer: option A.
A physical change occurred in which the iron remained iron, but lost one of its physical properties
Explanation: magnetization and demagnetization is a physical change as no new substance is form and it is easily reversed. When an iron rod is magnetized, it can loss it magnetic property by hitting it. So when an iron rod which is magnetized falls from a height it can also loss its magnetic property
What you have to do is balance the chemical equations to make sure everything is even on both sides. If you want me to help you answer the questions comment back