Metals can be highly purified using electrolysis. Which equation best reflects the overall process of purifying copper?
A. Cu^+2(aq)cathode ---> Cu^+2(aq)anode
B. Cu^+2(aq)anode ---> Cu^+2(aq)cathode
C. Cu(s)cathode ---> Cu(s)anode
D. Cu(s)anode ---> Cu(s)cathode

A. Cu^+2(aq)cathode ---> Cu^+2(aq)anode

Explanation:

Electrolysis is the process in which current is passed through a solution thereby causing a chemical change at the anode and cathode. Copper is being purified using electrolysis by using impure copper at the anode and pure copper at the cathode. This pure and impure copper are placed in a copper(ii)sulfate electrolyte solution and dc current is made to pass through it.  The resulting changes at the anode and cathode are given by the equation:

cathode: Cu²⁺  + 2e⁻    ⇒     Cu

anode:    Cu     ⇒       Cu²⁺  + 2e⁻

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the best answer is d because the strong cohesion is caused by the ability of water molecules to undergo hydrogen bonding.

a is incorrect because when water solidifies, it becomes   ice, which expands and occupies a bigger volume for the same mass of water in its liquid state.

b is incorrect because water has high surface tension. besides bonding to itself it hydrogen bonds to other molecules at the top decreasing possibility for breaking of attractive forces.

c is incorrect because the water molecule has oxygen which is highly electronegative and so pulls the electron pair towards itself creating a dipole moment, making the molecule polar.

e is incorrect because water has strong adhesion, ability to stick to other molecules such as glass because of this molecules having stronger hydrogen bonding than water.