The reduction reaction is the gain of electrons while oxidation reaction is the loss of electrons. For potassium ion(K+), the reaction should be K+ + e- ==> K. So the answer is (1).
They have same mass
Explanation:
If you think wisely 100 pounds and 100 pounds have the same weight so the answer is equal
Zn(NO3)2 + Cu will be the result of this single displacement (replacement) reaction :))
