When performing a math equation, the answer cannot have any more then the
measurement with the
number of
significant figures.

a electronegativity decreases beacuse the size of nucleus is bigger.

the answer is c. nacl

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

i belive it is water