ionic bond:
Bond formed when an atom donates its electron and other atom receives those electrons.
polar covalent:
Bond formed by equal sharing of electrons between both the atoms and there is an electronegativity difference between the two atoms.
Nonpolar covalent:
Bond formed by equal sharing of electrons between both the atoms and there is no electronegativity difference between the two atoms.
Metallic:
Formed between two metals.
So the bond between :
Phosphorus and chlorine-polar covalent bond as it is formed by equal sharing of electrons between both the atoms and there is an electronegativity difference between the two atoms.
Potassium and oxygen -ionic bond as here potassium donates its electron and oxygen receives those electrons
Fluorine and fluorine -Non polar covalent bond as formed by equal sharing of electrons between both the atoms and there is no electronegativity difference between the two atoms.
Copper and aluminum-metallic bond as Formed between two metals.
Carbon and fluorine -polar covalent bond as it is formed by equal sharing of electrons between both the atoms and there is an electronegativity difference between the two atoms.
Carbon and hydrogen --Non polar covalent bond as formed by equal sharing of electrons between both the atoms and there is no electronegativity difference between the two atoms.
Aluminum and oxygen--ionic bond as here aluminum donates its electron and oxygen receives those electrons
Silver and copper --metallic bond as Formed between two metals.
Answer : The correct option is, 0.21 moles
Solution : Given,
Molarity of the solution = 0.85 M = 0.85 mole/L
Volume of solution = 250 ml = 0.25 L 
Molarity : It is defined as the number of moles of solute present in one liter of the solution.
Formula used :
Now put all the given values in this formula, we get the moles of solute of the solution.
Therefore, the moles of solute is, 0.21 moles
Answer:
Be,Mg,Ca,Sr,Ba.Ra[down the group electronegativity is decreasing]
Explanation:
