Out of what material did coal form?
A. Sea organisms
B. Plant material
C. Limestone
D. Dinosaur fossils

a is the correct answer

it is b that is the answer.

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

c. orbital shape i hope this is correct