What difficulty was faced by scientists after gathering information about the properties of elements?

11 players on a field that has a maximum of 11 players

it's filtration, but this is an assumption so my apologies if i got this

the answer is d.) potassium

the dissociation of nickel hydroxide is follows:

the concentration of hydroxide ion is

the equilibrium constant value of nickel hydroxide is = 6.1 * 10^-^1^6 and thus equilibrium equation can be written as:

thus, concentration of ni is 0.23 * 10^-^4 mol /l