Final answer:
The formation of hydrogen gas is not a temporary effect of the positive pole of the galvanic current; it usually occurs at the cathode, not the anode.
The NOT a temporary effect of the positive pole of galvanic current is 2) Acidic reaction.
Step-by-step explanation:
The positive pole of the galvanic current typically results in acidic reactions, muscle contractions, and the stimulation of nerves due to the migration of positive ions towards the cathode.
However, the formation of hydrogen gas is not a direct effect of the positive pole; it is typically observed at the negative pole (cathode) where reduction reactions occur. In a galvanic cell, the reaction at the cathode often involves the reduction of H+ ions to hydrogen gas. Therefore, formation of hydrogen gas is the temporary effect that does not occur at the positive pole (anode) of the galvanic current.
When a galvanic cell is in operation, a chemical reaction occurs at the electrodes. At the positive pole (cathode), reduction reaction happens, and hydrogen gas is evolved, while at the negative pole (anode), the oxidation reaction takes place.
For example, in the given reaction, 3 Sn(s) + 2NO3(aq) +8 H+ (aq) → 3 Sn² + (aq) +2 NO(g) + 4H₂O(1), the formation of hydrogen gas is observed at the platinum electrode, which is the positive pole of the galvanic cell.