2.75x10^-4 mol NaOH= g H2O

pure substance: iron,copper

impure substance: water,charcoal

i think it's c. if you look search electronic symbol on google and then click on wiki it shows you a

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