Aluminum and copper because all of them have advantages and disadvantages over iron alloys.
I believe the first one is chemical, second one is mechanical, third one is mechanical and fourth one is chemical.
1) between calcium cations (Ca²⁺) and chloride anions (Cl⁻) and water, there is ion-dipole attractions. <span>An ion-dipole force is an attractive force that results from the electrostatic attraction between an ion (Ca</span>²⁺ and Cl⁻)<span> and a neutral molecule that has a dipole (H</span>₂O).
2) between ethanol (CH₃CH₂OH) and water, there is hydrogen bonding, because both molecules have oxygen and hydrogen.