Which statement is true about this reaction?

A) It is a practical source of energy on Earth.
B) It occurs only outside the solar system.
C) Its product is heavier than each of its reactants.
D) It shows the critical mass of an element.

A) It is a practical source of energy on Earth

Explanation:

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