Earth’s mantle is a.
a layer of molten metal.
b.
a layer of hot rock.
c.
a dense ball of solid metal.
d.
a layer of rock that forms Earth’s outer skin.

layer of hot rock

hope it helps !

answer: i would say b.

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