First you need to know the different between an ionic and covalent bond. An ionic bond is the pairing of a metal and non-metal element. A covalent bond is the pairing of 2 nonmetals.
Metals are the elements at the left of the periodic table while non-metals are the elements at the right of the periodic table.
You should also know the diatomic (di means 2) molecules also known as the fab 7. These molecules will always form covalent bonds. These molecules are hydrogen, nitrogen, oxygen, fluorine, chlorine, bromine, and iodine. With the subscripts, these molecules would be written as H ₂, N ₂, O ₂, F ₂, Cl ₂, Br ₂, and I ₂.
More than one million Earths could fit inside the Sun if it were hollow. The Sun has a radius of 696.340 km / 432.685 mi and a diameter of 1.39 million km / 864.000 mi.
Answer:
No reaction
Explanation:
Single-displacement reaction is the chemical reaction in which one metal which has higher negative redox potential replaces the another from it's salt solution.
Thus, Cu cannot replaces zine from its salt as it is less reactive than zince.
However, zinc can replace copper from its salt as:

D.
Blue litmus paper turns red when placed in a base.